Use maximum precision in assembly version

It's important we support side-by-side installs of different GitHub for
VS and GitHub Essentials versions.

version.json

@@ -5,6 +5,9 @@
     "^refs/heads/master$",
     "^refs/heads/v\\d+(?:\\.\\d+)?$"
   ],
+  "assemblyVersion": {
+    "precision": "revision"
+  },
   "cloudBuild": {
     "buildNumber": {
       "enabled": false