convert to requirements.txt

.github/workflows/photon-api-docs.yml

@@ -82,7 +82,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install mkdocs mkdocs-material mkdocstrings[python] mkdocs-gen-files mkdocs-literate-nav mkdocs-section-index mkdocs-exclude
+          pip install -r photon-lib/py/docs/requirements.txt
 
       - name: Build MkDocs site
         run: mkdocs build

photon-lib/py/docs/requirements.txt

@@ -0,0 +1,7 @@
+mkdocs==1.4.0
+mkdocs-material==9.0.0
+mkdocstrings[python]==0.19.0
+mkdocs-gen-files==0.5.0
+mkdocs-literate-nav==0.5.0
+mkdocs-section-index==0.3.5
+mkdocs-exclude==1.0.2