Add .gitattributes to identify generated files to GitHub

Author: mdbooth

.gitattributes

@@ -0,0 +1,12 @@
+# Tell GitHub about generated files
+
+# deepcopy and conversion-gen
+zz_generated.* linguist-generated=true
+
+# Generated parts of manifests
+/config/crd/bases/infrastructure.cluster.x-k8s.io_*.yaml linguist-generated=true
+/config/webhook/manifests.yaml linguist-generated=true
+/config/rbac/role.yaml linguist-generated=true
+
+# Generated API docs
+/docs/book/src/api/*/** linguist-generated=true