Add Linux AArch64 wheel build support

.github/workflows/main.yml

@@ -67,15 +67,24 @@ jobs:
             path: dist/*.tar.gz
 
   wheel:
-    name: ${{ matrix.os }}-wheel
+    name: ${{ matrix.os }},${{ matrix.arch }}-wheel
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-latest,  macos-latest]
+        arch: [auto]
+        include:
+          - os: ubuntu-latest
+            arch: aarch64
 
     steps:
     - uses: actions/checkout@v2
 
+    - name: Set up QEMU
+      if: ${{ matrix.arch == 'aarch64' }}
+      uses: docker/setup-qemu-action@v1
+
     - name: Set up Python 3.8
       uses: actions/setup-python@v2
       with:
@@ -88,7 +97,8 @@ jobs:
     - name: Build
       env:
         CIBW_BUILD: "cp36-* cp38-* pp36-*"
-        CIBW_SKIP: "*-win32 *-manylinux_i686 pp27-* cp27-* cp35-*"
+        CIBW_SKIP: "*-win32 *-manylinux_i686 pp27-* cp27-* cp35-* *-musllinux_aarch64"
+        CIBW_ARCHS: ${{matrix.arch}}
         CIBW_BEFORE_BUILD_LINUX: yum -y install protobuf-devel protobuf-compiler python3-devel
         CIBW_REPAIR_WHEEL_COMMAND_LINUX: "auditwheel repair --lib-sdir . -w {dest_dir} {wheel}"
         CIBW_BEFORE_BUILD_MACOS: brew install protobuf