gosec govulncheck runs (#1)

* gosec govulncheck runs

* Fix flaky TestRateLimiter_Matrix test

The test was failing due to two issues:
1. Test name generation used invalid character conversion (string(rune('0'+limit)))
   which produced non-printable characters for limits >= 10
2. Using 10ms windows with 100 requests caused race conditions - early requests
   would expire before all 100 were made, allowing the 101st request

Changed to use struct-based test cases with proper fmt.Sprintf naming and
a consistent 1-second window that won't expire during rapid test execution.

.github/workflows/pr.yaml

@@ -9,8 +9,14 @@ on:
       - "**"
       - "!main"
 
+permissions:
+  contents: write
+  actions: write
+  pull-requests: write
+  security-events: write
+
 jobs:
   pr-checks:
     uses: lukaszraczylo/shared-actions/.github/workflows/go-pr.yaml@main
     with:
-      go-version: "1.24"
+      go-version: ">=1.24"