feat: inform users of breaking changes on first run (#619)

BREAKINGCHNAGES_dev.md

@@ -0,0 +1,12 @@
+1. In 13.0.0, we introduced a new feature, pushing git repos, now this feature 
+   has been removed as some users are not satisfied with it.
+
+   For configuration entries, the following ones are gone:
+
+   ```toml
+   [git]
+   pull_only_repos = []
+   push_only_repos = []
+   pull_arguments = ""
+   push_arguments = ""
+   ```