dependabot: ignore updates to actions/stale and dessant/lock-threads

.github/dependabot.yml

@@ -5,6 +5,10 @@ updates:
     directory: /
     schedule:
       interval: daily
+    # The actions in triage-issues.yml are updated in the Homebrew/.github repo
+    ignore:
+      - dependency-name: actions/stale
+      - dependency-name: dessant/lock-threads
 
   - package-ecosystem: bundler
     directory: /docs