schema: drop id from umask

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

Author: giuseppe

schema/config-schema.json

@@ -93,7 +93,6 @@
                             "$ref": "defs.json#/definitions/GID"
                         },
                         "umask": {
-                            "id": "https://opencontainers.org/schema/bundle/process/user/umask",
                             "$ref": "defs.json#/definitions/Umask"
                         },
                         "additionalGids": {