Build wheels with cibuildwheels on GitHub Actions

Fixes mkleehammer#175
Ref mkleehammer#688
Closes mkleehammer#668
Closes mkleehammer#685
Fixes mkleehammer#441 and pretty much most issues that mention
` sql.h: No such file or directory`

This also need to setup some PyPI keys for automated uploads.

.github/workflows/ubuntu_build.yml

@@ -191,3 +191,23 @@ jobs:
       run: |
         cd "$GITHUB_WORKSPACE"
         python "./${{ matrix.tests-dir }}/mysqltests.py" "DRIVER={MySQL ODBC 8.0 ANSI Driver};SERVER=localhost;UID=root;PWD=root;DATABASE=test;CHARSET=utf8mb4"
+
+  build_wheels:
+    name: Build wheels on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, windows-2019, macos-10.15]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Build wheels
+        uses: pypa/[email protected]
+        # to supply options, put them in 'env', like:
+        # env:
+        #   CIBW_SOME_OPTION: value
+
+      - uses: actions/upload-artifact@v2
+        with:
+          path: ./wheelhouse/*.whl