Update gitattributes to improve PR file visilibity
This change adds more golden files to have a `linguist-generated=true`
setting so that they are not displayed in PRs.
Cargo.lock files are set with `linguist-generated=false` so that these
changes are not hidden in PRs.
-# By default, collapse for these files in GitHub reviews.
+# Expand these files in PRs:
go.sum linguist-generated=false
+**/Cargo.lock linguist-generated=false
+# Collapse these files in PRs:
controller/gen/**/*.pb.go linguist-generated=true
**/*.golden linguist-generated=true
+**/*.golden.yml linguist-generated=true
+controller/proxy-injector/fake/data/* linguist-generated=true
