GHA: Fetch full git history for windows

[yhabteab]

Quote from https://github.com/actions/checkout:

Only a single commit is fetched by default, for the ref/SHA that triggered the workflow. Set fetch-depth: 0 to fetch all history for all branches and tags

Fixes the Windows GHA from #10383:
https://github.com/Icinga/icinga2/actions/runs/15064535939/job/42346335042?pr=10383

C:\a\icinga2\icinga2\Build_CPack_Packages\win32\WIX\main.wxs(8) : error CNDL0108 : The Product/@Version attribute's value, '083ab56', is not a valid version. Legal version values should look like 'x.x.x.x' where x is an integer from 0 to 65534.

C:\a\icinga2\icinga2\Build_CPack_Packages\win32\WIX\main.wxs(8) : error CNDL0010 : The Product/@Version attribute was not found; it is required.

[julianbrost]

I'm not sure how much sense this makes as a separate PR instead of pushing this to #10383 directly, that's where the testing for whether it fixes that problem would happen anyway.