Fix google_identity_group. (#3996) (#2507)

* This resource has a newly-mandatory enum field.

The enum has only one possible value and seems to be required in all cases.
This broke all existing terraform customers - and likely all API clients.
It has not been fixed in the autogenerated API tools, and it is not reflected in the docs.
I have reached out to the team to see if there is a possibility of fixing the existing customers.

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

.changelog/3996.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+Fixed upstream breakage of `google_identity_group`.
+```

google-beta/resource_cloud_identity_group.go

@@ -167,7 +167,7 @@ func resourceCloudIdentityGroupCreate(d *schema.ResourceData, meta interface{})
 		obj["labels"] = labelsProp
 	}
 
-	url, err := replaceVars(d, config, "{{CloudIdentityBasePath}}groups")
+	url, err := replaceVars(d, config, "{{CloudIdentityBasePath}}groups?initialGroupConfig=EMPTY")
 	if err != nil {
 		return err
 	}