update with CF_GIT_BRANCH required variable (#540)

Author: dustinvanbuskirk

incubating/codefresh-report-image/step.yaml

@@ -60,7 +60,8 @@ spec:
       "patterns": [],
       "required": [
         "CF_API_KEY",
-        "CF_IMAGE"
+        "CF_IMAGE",
+        "CF_GIT_BRANCH"
       ],
       "properties": {
         "CF_API_KEY": {