Change puppetdb version to 6

Author: hestonhoffman

source/_config.yml

@@ -107,7 +107,16 @@ documents:
     hide: true
   /puppetdb/6.y:
     doc: puppetdb
-    version: "6.13"
+    version: "6.y"
+    nav: ./_puppetdb_nav.html
+    external_source:
+      repo: git://github.com/puppetlabs/puppetdb.git
+      commit: doc-6.y
+      subdirectory: documentation
+    hide: true
+  /puppetdb/6:
+    doc: puppetdb
+    version: "6"
     nav: ./_puppetdb_nav.html
     external_source:
       repo: git://github.com/puppetlabs/puppetdb.git