Add note about lockfile formatting

Author: hsbt

_posts/2025-12-03-upgrade-to-rubygems-bundler-4.md

@@ -183,6 +183,10 @@ git "https://my_git_repo_with_gems" do
 end
 ```
 
+### Change Ruby and Bundler version format
+
+In the `BUNDLED WITH` and `RUBY` sections of the lockfile, we fixed the three space indentation to be just two spaces, to be consistent with the rest of the lockfile format. and we also removed the patch version from the Ruby version, since it's not relevant for Bundler.
+
 ## Bundler 4: Cache behavior changes
 
 ### Git and Path gems are included in `vendor/cache` by default