use mlugg/setup-zig instead of goto-bus-stop/setup-zig

The 'goto-bus-stop' action is no longer maintained and uses outdated
methods for getting the Zig toolchain. Instead use the one maintained
by mlugg, which uses the mirror system and is generally better.

Author: Rexicon226

.github/workflows/test.yml

@@ -123,7 +123,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Install zig
-      uses: goto-bus-stop/setup-zig@v2
+      uses: mlugg/setup-zig@v2
       with:
         version: 0.14.1
 
@@ -143,7 +143,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Install zig
-      uses: goto-bus-stop/setup-zig@v2
+      uses: mlugg/setup-zig@v2
       with:
         version: 0.14.1