ci: limit blast radius of ARM64 Alpine CI workaround

It's documented to not have any effect on non-ARM64 architectures, but
let's not run it on any other architecture, just in case and to improve
implicit documentation.

Author: AlexTMjugador

.github/workflows/ci.yml

@@ -158,7 +158,7 @@ jobs:
 
     steps:
       - name: 🩹 Work around https://github.com/actions/runner/issues/801
-        if: endsWith(matrix.target, '-linux-musl')
+        if: endsWith(matrix.target, '-linux-musl') && runner.arch == 'ARM64'
         uses: laverdet/alpine-arm64@v1
 
       - name: 🧰 Install glibc Linux toolchain packages