freeze Vale version

Author: aireilly

.github/workflows/vale-on-pull.yml

@@ -10,7 +10,8 @@ jobs:
       - uses: actions/checkout@v3
       - uses: errata-ai/vale-action@reviewdog
         with:
-          filter_mode: added
+          version: 2.30.0
+          filter_mode: diff_context
           vale_flags: "--no-exit --minAlertLevel=error --glob=*.adoc"
           reporter: github-pr-review
           fail_on_error: false