Add the requirements to the build environment.

.github/workflows/main.yml

@@ -100,6 +100,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+
       # Used to host cibuildwheel
       - uses: actions/setup-python@v5