ci: build for alpine arm (#960)

Author: sbdchd

.github/workflows/rust.yml

@@ -53,6 +53,13 @@ jobs:
             vscode_artifact_name: alpine-x64
             rustflags: "-C linker=rust-lld"
 
+          - name: Linux Alpine arm64
+            os: ubuntu-22.04
+            target: aarch64-unknown-linux-musl
+            artifact_name: squawk-linux-musl-arm64
+            vscode_artifact_name: alpine-arm64
+            rustflags: "-C linker=rust-lld"
+
           - name: Windows x86_64
             os: windows-latest
             target: x86_64-pc-windows-msvc
@@ -79,7 +86,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Update apt repositories
-        if: matrix.target == 'aarch64-unknown-linux-gnu' || matrix.target == 'aarch64-unknown-linux-gnu'
+        if: matrix.target == 'aarch64-unknown-linux-gnu' || matrix.target == 'x86_64-unknown-linux-musl'
         run: sudo apt-get update
 
       - name: Install AArch64 target toolchain