When describing the current commit, exclude the Dev tag (#226)

* When describing the current release, exclude the Dev tag

* Only run the release task on non-dev tags (i.e. real release tags)

photon-server/versioningHelper.gradle

@@ -8,7 +8,7 @@ gradle.allprojects {
         String tagIsh
         try {
             exec {
-                commandLine 'git', 'describe', '--tags'
+                commandLine 'git', 'describe', '--tags', '--exclude="Dev"'
                 standardOutput = stdout
             }
             tagIsh = stdout.toString().trim().toLowerCase()