Merge pull request gitpython-developers#90 from EliahKagan/ci-install

Test installing project on CI

Author: Byron

.github/workflows/pythonpackage.yml

@@ -26,10 +26,10 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: true
-    - name: Install dependencies
+    - name: Install project and dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install .
     - name: Lint with flake8
       run: |
         pip install flake8