init git config failure -> warn

[phanirithvij]

closes #391

[fraggerfox]

I can confirm the patch works and opengist does spew out the warning (instead of stopping immediately), when I am running it without any containers

{"level":"info","caller":"github.com/thomiceli/opengist/internal/cli/main.go:96","time":"2024-11-27T02:10:52+05:30","message":"Data directory: /usr/local/www/opengist"}
{"level":"warn","caller":"github.com/thomiceli/opengist/internal/cli/main.go:99","time":"2024-11-27T02:10:52+05:30","message":"Git config modification failed, ensure /usr/local/www/opengist is added to git safe directories, and receive.advertisePushOptions is set to true."}

[thomiceli]

Thanks for the PR. Took the liberty to change the message. LMK

[phanirithvij]

LGTM