Add pre-commit ecosystem to Dependabot

https://github.blog/changelog/2026-03-10-dependabot-now-supports-pre-commit-hooks/

https://docs.github.com/en/code-security/reference/supply-chain-security/dependabot-options-reference#package-ecosystem-

Author: jbampton

.github/dependabot.yml

@@ -13,3 +13,9 @@ updates:
       interval: "daily"
     cooldown:
       default-days: 7
+  - package-ecosystem: "pre-commit"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    cooldown:
+      default-days: 7