Make application element optional in app.yaml
This change was introduced in the 1.8.4 SDK.
@@ -1501,7 +1501,7 @@ class AppInfoExternal(validation.Validated):
ATTRIBUTES = {
- APPLICATION: APPLICATION_RE_STRING,
+ APPLICATION: validation.Optional(APPLICATION_RE_STRING),
MODULE: validation.Optional(MODULE_ID_RE_STRING),
VERSION: validation.Optional(MODULE_VERSION_ID_RE_STRING),
RUNTIME: RUNTIME_RE_STRING,
