Update list of allowed post tags

Tags other than "news" on posts are not getting rendered on post
pages because they are not in the allowed list.

The problem remains that the tag archive pages are not being generated.

Change-Id: I4d483a4f6dd8f23908b7b014194dc94349f512cb
diff --git a/_data/tags.yml b/_data/tags.yml
index 79d2545..1d3fb4c 100644
--- a/_data/tags.yml
+++ b/_data/tags.yml
@@ -2,14 +2,7 @@
 # If you are using the createtag script, don't leave an blank line at the end of this file.
 # In other words, the last line must be the last tag in the allowed-tags list.
 allowed-tags:
-  - getting_started
-  - content_types
-  - navigation
-  - formatting
-  - publishing
-  - single_sourcing
-  - special_layouts
-  - collaboration
+  - hackathon
   - news
-  - troubleshooting
-  - mobile
+  - summit
+  - ux