ci: add musl target (static linking) to release workflow

Author: drewstone

.github/workflows/release.yml

@@ -36,6 +36,9 @@ jobs:
           - target: x86_64-unknown-linux-gnu
             os: ubuntu-latest
             use_cross: true
+          - target: x86_64-unknown-linux-musl
+            os: ubuntu-latest
+            use_cross: true
           - target: aarch64-unknown-linux-gnu
             os: ubuntu-latest
             use_cross: true