add macos-10.15/universal2

Author: jswhit

.github/workflows/build-wheels.yml

@@ -24,8 +24,7 @@ jobs:
 
       fail-fast: false
       matrix:
-        #python-version: [ "3.6", "3.7", "3.8", "3.9", "3.10" ]
-        python-version: [ "3.9", "3.10" ]
+        python-version: [ "3.6", "3.7", "3.8", "3.9", "3.10" ]
         os: [ubuntu-latest, macos-latest]
         platform: [x64, x32]
         exclude:
@@ -47,6 +46,12 @@ jobs:
           - python-version: "3.10"
             os: ubuntu-latest
             platform: aarch64
+          - python-version: "3.9"
+            os: macos-10.15
+            platform: x86_64
+          - python-version: "3.10"
+            os: macos-10.15
+            platform: x86_64
     env:
       REPO_DIR: netcdf4-python
       PKG_NAME: netcdf4-python
@@ -81,7 +86,8 @@ jobs:
         if [ "macos-latest" == "${{ matrix.os }}" ]; then echo "TRAVIS_OS_NAME=osx" >> $GITHUB_ENV; else echo "TRAVIS_OS_NAME=${{ matrix.os }}" >> $GITHUB_ENV; fi
         if [ "schedule" == "${{ github.event_name }}" ]; then echo "TRAVIS_EVENT_TYPE=cron" >> $GITHUB_ENV; else echo "TRAVIS_EVENT_TYPE=${{ github.event_name }}" >> $GITHUB_ENV; fi
         if [ "schedule" == "${{ github.event_name }}" ]; then echo "BUILD_COMMIT=master" >> $GITHUB_ENV; else echo "BUILD_COMMIT=$BUILD_COMMIT" >> $GITHUB_ENV; fi
-        if [ "macos-latest" == "${{ matrix.os }}" ] && [ "$MB_PYTHON_VERSION" == "3.10" ]; then echo "PLAT=universal2" >> $GITHUB_ENV; fi
+        # make universal2 wheels on macos 10.15 by cross-compiling
+        if [ "macos-10.15" == "${{ matrix.os }}" ]; then echo "PLAT=universal2" >> $GITHUB_ENV; fi
 
     - name: Setup Special Environment variables for Linux AArch64
       if: ${{ matrix.platform == 'aarch64' }}