fix: migrate to GitHub action mlugg/setup-zig@v2

Author: guidoschmidt

.github/workflows/build.yaml

@@ -18,7 +18,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Setup Zig
-        uses: goto-bus-stop/setup-zig@v1
+        uses: mlugg/setup-zig@v2
         with:
           version: master