Add specific Musl build

.github/workflows/build-wheels.yml

@@ -11,6 +11,12 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
+        build: [null]
+        skip: ["pp* *-musllinux_*"]  # Skip PyPy and musl.
+        include:
+          - os: ubuntu-latest
+            build: "*-musllinux_*"
+            skip: "cp37-musllinux_* cp38-musllinux_*" # skip unsupported by NumPy
 
     steps:
       - uses: actions/checkout@v3
@@ -33,7 +39,8 @@ jobs:
           # Platform options
           CIBW_ARCHS_MACOS: "x86_64 arm64"
           CIBW_PROJECT_REQUIRES_PYTHON: ">=3.7,<3.13"
-          CIBW_SKIP: "pp*"  # Skip PyPy.
+          CIBW_BUILD: ${{ matrix.build }}
+          CIBW_SKIP: ${{ matrix.skip }}
           CIBW_MANYLINUX_X86_64_IMAGE: "manylinux2014"
           CIBW_ARCHS_LINUX: x86_64 aarch64
           # Testing