CI: github actions build

.github/workflows/build.yaml

@@ -0,0 +1,34 @@
+name: Build
+on:
+- push
+- pull_request
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os:
+        - ubuntu-latest
+        - windows-latest
+        - macOS-latest
+        python-version:
+        - "3.6"
+        - "3.8"
+        networkx-version:
+        - "1.*"
+        - "2.*"
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        pip install networkx==${{ matrix.networkx-version }}
+        python -m pip install --upgrade pip
+        pip install ".[dev]"
+    - name: Run pre-commit
+      uses: pre-commit/action@v2.0.0
+    - name: Test with pytest
+      run: pytest --color=yes

setup.cfg

@@ -32,7 +32,7 @@ keywords =
 packages = obonet
 zip_safe = False
 include_package_data = True
-python_requires = >=3
+python_requires = >=3.5
 install_requires =
     networkx