Extend GHA documentation to specify requirements file

.github/workflows/github_pages.yml

@@ -9,7 +9,7 @@ on:
       requirements:
         required: false
         default: "pelican"
-        description: "The Python requirements to install, for example to enable markdown and typogrify use: 'pelican[markdown] typogrify'"
+        description: "The Python requirements to install, for example to enable markdown and typogrify use: 'pelican[markdown] typogrify' or if you have a requirements file use: '-r requirements.txt'"
         type: string
       output-path:
         required: false
@@ -58,4 +58,3 @@ jobs:
       - name: Deploy to GitHub Pages
         id: deployment
         uses: actions/deploy-pages@v2
-

docs/tips.rst

@@ -187,6 +187,8 @@ the workflow:
 |              |          | install, for example to enable    |        |               |
 |              |          | markdown and typogrify use:       |        |               |
 |              |          | ``"pelican[markdown] typogrify"`` |        |               |
+|              |          | or if you have a requirements     |        |               |
+|              |          | file: ``"-r requirements.txt"``   |        |               |
 +--------------+----------+-----------------------------------+--------+---------------+
 | output-path  | No       | Where to output the generated     | string | ``"output/"`` |
 |              |          | files (``pelican``'s ``--output`` |        |               |