Simple GithubAction for CI testing

This is probably broken atm (adding here so it will trigger)

Author: eriknw

.github/workflows/test.yml

@@ -0,0 +1,40 @@
+name: python-suitesparse-graphblas
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-latest", "macos-latest", "windows-latest"]
+        python-version: [3.7, 3.8, 3.9]
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Conda
+      uses: conda-incubator/setup-miniconda@v2
+      with:
+        auto-update-conda: true
+        python-version: ${{ matrix.python-version }}
+        channels: conda-forge
+    - name: Build
+      run: |
+        conda info
+        conda list
+        conda install -c conda-forge cffi cython numpy graphblas pytest coverage black flake8  # TODO: environment.yml
+        python setup.py build_ext --inplace
+        python setup.py develop
+    - name: Test
+      env:
+        CYTHON_COVERAGE: true
+      run: |
+        coverage run --branch -m pytest
+    - name: Lint
+      run: |
+        black *py suitesparse_graphblas --check --diff
+        flake8 *py suitesparse_graphblas