Combine pip install command

.github/workflows/pythonapp.yml

@@ -268,8 +268,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -r requirements.txt
-          pip install -r doc/requirements.txt
+          pip install -r requirements.txt -r doc/requirements.txt
       - name: Test to check for CVEs for python requirements and HTML report dependencies
         run: |
           pytest test/test_requirements.py