CI: update mlugg/setup-zig to v2

Author: Techatrix

.github/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup Zig
-        uses: mlugg/setup-zig@v1
+        uses: mlugg/setup-zig@v2
 
       - name: Check Formatting
         run: zig fmt --ast-check --check .