chore: update CI to Zig 0.15.1

Author: lox

.github/workflows/build.yml

@@ -11,7 +11,7 @@ jobs:
       contents: read
     steps:
       - uses: actions/checkout@v4
-      - uses: mlugg/setup-zig@v1
+      - uses: mlugg/setup-zig@v2
         with:
-          version: 0.14.0
+          version: 0.15.1
       - run: zig build test --summary all