Change Dependabot schedule from daily to weekly

Daily action update PRs create unnecessary noise. Weekly is sufficient
for keeping GitHub Actions up to date while reducing PR churn.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dguido

.github/dependabot.yml

@@ -16,4 +16,4 @@ updates:
         patterns:
           - "*"
     schedule:
-      interval: daily
+      interval: weekly