Fix beta builds

The extension's beta name strings were missing.

Change-Id: I0245671c627aced507a9c6460bd6b852aaf1ebaa
diff --git a/.gitignore b/.gitignore
index 99bc392..a663a39 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 out/
 src/manifest.json
+.DS_Store