Update CI to Zig 0.16.0

Author: lalinsky

.github/workflows/test.yml

@@ -20,7 +20,7 @@ jobs:
     - name: Setup Zig
       uses: mlugg/setup-zig@v2
       with:
-        version: 0.15.2
+        version: 0.16.0
 
     - name: Build
       run: zig build