Fix CI: install Zig directly, disable Go cache without go.sum

The mlugg/setup-zig action mirrors 404 on Zig 0.14.1. Download from
the official release URL instead. Disable Go dependency caching since
GildedRose has no external dependencies (no go.sum).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: georgeglarson

.github/workflows/ci.yml

@@ -29,9 +29,10 @@ jobs:
         working-directory: MissingNumber
     steps:
       - uses: actions/checkout@v4
-      - uses: mlugg/setup-zig@v1
-        with:
-          version: 0.14.1
+      - name: Install Zig 0.14.1
+        run: |
+          curl -L https://ziglang.org/download/0.14.1/zig-linux-x86_64-0.14.1.tar.xz | tar -xJ
+          echo "$PWD/zig-linux-x86_64-0.14.1" >> "$GITHUB_PATH"
       - run: make test
 
   morse-code:
@@ -69,6 +70,7 @@ jobs:
       - uses: actions/setup-go@v5
         with:
           go-version: "1.22"
+          cache: false
       - run: make test
 
   restaurant-reviews: