Bump taskcluster_yml_validator in pre-commit configuration to v0.0.4

The latest version of taskcluster_yml_validator brings support for generic-worker
payloads, which we will use for Windows tasks (ref #122).

Author: marco-c

.pre-commit-config.yaml

@@ -9,7 +9,7 @@ repos:
     -   id: check-json
         exclude: enums/templates/json.json
 -   repo: https://github.com/marco-c/taskcluster_yml_validator
-    rev: v0.0.3
+    rev: v0.0.4
     hooks:
       - id: taskcluster_yml
 -   repo: local