v1.0 Support for flattening headers

What's Changed

• XOL-6302 Symfony 4.4 Upgrade by @anush in #14
• XOL-6654 Flattening the headers in ExcelWriter according to updated report structure by @last-stand in #15

Full Changelog: v0.8...v0.9

v0.8 Support separators and formatting

XOL-5937 Handle separators and formatting (#13)

v0.7 Support for Symfony 3

XOL-4975 Support for Symfony 3 (#12)

* XOL-4975 removed `composer.lock` from version control

* XOL-4975 fixed Symfony 2.8 deprecations

* XOL-4975 upgraded to phpunit 7

* XOL-4975 fixed phpunit config issue

* XOL-4975 fixed phpunit `setUp` function signature

* XOL-4975 fixed phpunit `setUp` function signature

* XOL-4975 fixed phpunit `tearDown` function signature

* XOL-4975 do not fail on warnings

Upgrade to PHPSpreadsheet

XOL-4064 Upgrade to PHPSpreadsheet (#9)

XOL-4064 Upgrade to PHPSpreadsheet

v0.5.1 Date Time Formatting

CS-3381 Flexible date formatting (#7)

v0.5 Set DateTime format on applicable cells

CS-3381 Set date time formats when export contains DATEVALUE and TIME…

v0.4 Bug Fix

Merge pull request #5 from mightytroll/XOL-3823

XOL-3823 Report Builder - Exports

v0.3 Fix to write 0 values into excel cells

Merge pull request #4 from rushi/XOL-2734

XOL-2734 Fix for writing 0 integer values into the cell

v0.2 Fix auto column width for multi-row headers

Merge pull request #3 from rushi/XOL-2734

XOL-2734 Fix column auto-width calculation

v0.1 Draft release

Merge pull request #2 from rushi/XOL-2733

XOL-2733 Better abstraction of report writers