Update references from master to main. (#232)

* Update references from master to main.

* Update publicReleaseRefSpec refs to main.

Co-authored-by: Guy Acosta <47648296+guyacosta@users.noreply.github.com>

version.json

@@ -2,7 +2,7 @@
   "$schema": "https://raw.githubusercontent.com/AArnott/Nerdbank.GitVersioning/master/src/NerdBank.GitVersioning/version.schema.json",
   "version": "1.2",
   "publicReleaseRefSpec": [
-    "^refs/heads/master$",
+    "^refs/heads/main",
     "^refs/heads/v\\d+(?:\\.\\d+)?$"
   ],
   "cloudBuild": {
@@ -10,4 +10,4 @@
       "enabled": true
     }
   }
-}
+}