.github: add a Github Action CI

First time I ever do this, so it's a basic copy paste of their example.

Signed-off-by: Antoine Poinsot <darosior@protonmail.com>

Author: darosior

.github/workflows/python-package.yml

@@ -0,0 +1,34 @@
+name: python-bip32
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [3.5, 3.6, 3.7, 3.8]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Installation (deps and package)
+      run: |
+        python -m pip install --upgrade pip
+        pip install flake8 pytest
+        pip install -r requirements.txt -r tests/requirements.txt
+        python setup.py install
+    - name: Linter (flake8)
+      run: |
+        flake8 ./bip32/ --count --show-source --statistics --max-line-length=90
+    - name: Test with pytest
+      run: |
+        pytest -vvv