2 setup ci with GitHub actions (#26)

* Added 'CI' GitHub action

Runs pytest and black lint

* Separated installation, testing, and lint

GitHub actions now has three separate steps for these tasks

.github/workflows/ci.yml

@@ -0,0 +1,19 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.x'
+    - name: Install dependencies
+      run: pip install pytest black 
+    - name: Test with pytest
+      run: pytest 
+    - name: Lint code
+      run: black --check --line-length 80 .