Update build_documentation.yml

Testing documentation building through GitHub workflows.

.github/workflows/build_documentation.yml

@@ -7,27 +7,32 @@ on:
   pull_request:
     branches: 
       - main
+  workflow_dispatch:
 
 jobs:
   build:
 
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
-    
+    - uses: actions/checkout@v3
+
     - name: Set up Python 3.10
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: '3.10'
 
+    # Install dependencies
     - name: Upgrade pip, install package, install requirements, build docs
       run: |
-        pip install --upgrade pip
+        python -m pip install --upgrade pip
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
         pip install .
         if [ -f ./docs/requirements.txt ]; then pip install -r ./docs/requirements.txt; fi
         pip install sphinx
         sphinx-build docs ./docs/_build/html/
+      shell: bash
+
     # Create an artifact of the html output.
     - uses: actions/upload-artifact@v1
       with: