Please check 

from odoo import models
from odoo.fields import Date
from datetime import date, datetime
import dateutil.relativedelta

fs = Date.from_string
ts = Date.to_string


class CalibExcelReport(models.AbstractModel):
    _name = "report.calibration_tracking.calib_xlsx_document"
    _inherit = "report.report_xlsx.abstract"
    _description = "Calibration XLSX Report"

    def generate_xlsx_report(self, workbook, data, vals):
        cell_text_format = workbook.add_format({'align': 'center', 'bold': True, 'font_size': 12, 'bg_color': '#FF9933'})
        head = workbook.add_format({'align': 'center', 'bold': True,'size': 14, 'bg_color': '#6B8E23'})
        head1 = workbook.add_format({'align': 'left', 'bold': True, 'size': 12, 'bg_color': '#D3D3D3'})
        head2 = workbook.add_format({'align': 'left', 'size': 12})
        head3 = workbook.add_format({'align': 'left', 'bold': True, 'size': 12})
        format1 = workbook.add_format({'align': 'center', 'font_size': 10})
        format2 = workbook.add_format({'align': 'center', 'bold': True, 'font_size': 10, 'border': 1, 'bg_color': '#D3D3D3'})
        format3 = workbook.add_format({'align': 'center',  'font_size': 10, 'border': 1})
        format6 = workbook.add_format({'align': 'center', 'font_size': 10})
        worksheet = workbook.add_worksheet('Report')
        worksheet.set_column('A:A', 6,)
        worksheet.set_column('B:B', 20)
        worksheet.set_column('C:C', 20)
        worksheet.set_column('D:D', 20)
        worksheet.set_column('E:E', 20)
        worksheet.set_column('F:F', 20)
        worksheet.set_column('G:G', 20)
        worksheet.set_column('H:H', 20)
        worksheet.set_column('I:I', 20)
        worksheet.set_column('J:J', 25)
        worksheet.set_column('K:K', 20)
        worksheet.set_column('L:L', 20)
        row = 2
        column = 0

        worksheet.merge_range(row, column, row + 1, column + 12, 'Calibration Instrument Master List', head)
        row = 5
        column = 0

        worksheet.write(row, column, 'SL. No', cell_text_format)
        worksheet.write(row, column + 1, 'DESCRIPTION', cell_text_format)
        worksheet.write(row, column + 2, 'Range', cell_text_format)
        worksheet.write(row, column + 3, 'Make', cell_text_format)
        worksheet.write(row, column + 4, 'Sl.No', cell_text_format)
        worksheet.write(row, column + 5, 'ID NUMBER', cell_text_format)
        worksheet.write(row, column + 6, 'CALIBRATED ON', cell_text_format)
        worksheet.write(row, column + 7, 'CALIBRATION DUE', cell_text_format)
        worksheet.write(row, column + 8, 'LOCATION', cell_text_format)
        worksheet.write(row, column + 9, 'TEST CERTIFICATE NO', cell_text_format)
        worksheet.write(row, column + 10, 'STATUS/REMARKS', cell_text_format)
        worksheet.write(row, column + 11, 'VERIFIED ', cell_text_format)
        calibrations = []
        if data['date_range_based']:
            calibrations = self.env['instrument.calibration'].search([('last_due_date', '>=', data['from_date'])]).filtered(lambda s:s.last_due_date != False and s.last_calib_date != False)
        if data['month_based']:
            due_date = (date.today() + dateutil.relativedelta.relativedelta(months=int(data['notify_date'])))
            calibrations = self.env['instrument.calibration'].search([('last_due_date', '<=', due_date)]).filtered(lambda s:s.last_due_date != False and s.last_calib_date != False)
        calib_list = []
        if calibrations:
            i = 1
            for calib in calibrations:
                vals = {'no': i,
                        'desc': calib.product_desc,
                        'range': calib.range,
                        'make': calib.instrument_make.name if calib.instrument_make else False,
                        'sl': calib.sl_no,
                        'id_no': calib.id_number,
                        'calib_date': calib.last_calib_date.strftime('%d/%m/%Y') if calib.last_calib_date else False,
                        'calib_due': calib.last_due_date.strftime('%d/%m/%Y') if calib.last_due_date else False,
                        'location': calib.location_id.name if calib.location_id else False,
                        'cert_no': calib.last_certi_no,
                        'status': calib.status,
                        'verified': calib.calib_verify}
                calib_list.append(vals)
                i = i+1
        print(calib_list)
        row = 6
        for ca_list in calib_list:

            worksheet.write(row + 1, column + 0, ca_list['no'], format1)
            worksheet.write(row + 1, column + 1, ca_list['desc'], format1)
            worksheet.write(row + 1, column + 2, ca_list['range'], format1)
            worksheet.write(row + 1, column + 3, ca_list['make'], format1)
            worksheet.write(row + 1, column + 4, ca_list['sl'], format1)
            worksheet.write(row + 1, column + 5, ca_list['id_no'], format1)
            worksheet.write(row + 1, column + 6, ca_list['calib_date'], format1)
            worksheet.write(row + 1, column + 7, ca_list['calib_due'], format1)
            worksheet.write(row + 1, column + 8, ca_list['location'], format1)
            worksheet.write(row + 1, column + 9, ca_list['cert_no'], format1)
            worksheet.write(row + 1, column + 10, ca_list['status'], format1)
            worksheet.write(row + 1, column + 11, ca_list['verified'], format1)
            row +=1

Please try below code.

from openpyxl import Workbook

workbook = Workbook(write_only=False)
worksheet = workbook.active
worksheet.row_dimensions[1].height = 70

Please find the more information: https://www.geeksforgeeks.org/python-adjusting-rows-and-columns-of-an-excel-file-using-openpyxl-module/