Fixing the build failures from a missing GCS Key (#1480)

* Fixing the build failures from a missing GCS Key

Accidentally introduced in https://github.com/gomods/athens/pull/1428

* Adding a TODO to the drone build

* adding a step to test the Athens server startup

* Adding the JSONKey back to the default config

* use temporary image

* Switching back to the old env var for the GCS JSON Key

cc/ @marwan-at-work

* removing the ServiceAccount. we want to stick with JSONKey

* reverting to original key fetching code

* fixing build err

* bumping chart ver

config.dev.toml

@@ -301,14 +301,19 @@ SingleFlightType = "memory"
         # Env override: ATHENS_STORAGE_GCP_BUCKET
         Bucket = "MY_GCP_BUCKET"
 
-        # ServiceAccount is a base64 encoded service account
+        # JSONKey is a base64 encoded service account 
         # key that allows Athens to be run outside of GCP
         # but still be able to access GCS. If you are
         # running Athens inside GCP, you will most
         # likely not need this as GCP figures out
         # internal authentication between products for you.
+        # 
+        # NOTE: This config value is deprecated in favor of
+        # ServiceAccount above. Athens will check for it,
+        # but please do not rely on it being available forever.
+        #
         # Env override: ATHENS_STORAGE_GCP_JSON_KEY
-        ServiceAccount = ""
+        JSONKey = ""
 
     [Storage.Minio]
         # Endpoint for Minio storage