chore(docs) upgrade to Sphinx 4 and use requirements.txt

.github/workflows/compile_docs.yml

@@ -39,7 +39,7 @@ jobs:
         run: sudo apt-get install doxygen texlive-xetex texlive-binaries texlive-lang-english latexmk fonts-freefont-otf
       - name: Install requirements
         run: |
-          pip install --upgrade --upgrade-strategy eager Sphinx==3.5.4 breathe==4.30.0 recommonmark==0.6.0 commonmark==0.9.1 sphinx-rtd-theme==0.5.2 sphinx-markdown-tables==0.0.15 sphinx-sitemap==2.2.0
+          pip install -r docs/requirements.txt
       - name: Setup Emscripten cache
         id: cache-system-libraries
         uses: actions/cache@v2

.gitignore

@@ -11,6 +11,7 @@ docs/xml
 docs/out_latex
 docs/_static/built_lv_examples
 docs/LVGL.pdf
+docs/env
 out_html
 __pycache__
 /emscripten_builder

docs/requirements.txt

@@ -0,0 +1,34 @@
+alabaster==0.7.12
+Babel==2.9.1
+breathe==4.30.0
+certifi==2020.12.5
+chardet==4.0.0
+commonmark==0.9.1
+docutils==0.16
+idna==2.10
+imagesize==1.2.0
+importlib-metadata==4.0.1
+Jinja2==2.11.3
+Markdown==3.3.4
+MarkupSafe==1.1.1
+packaging==20.9
+Pygments==2.9.0
+pyparsing==2.4.7
+pytz==2021.1
+recommonmark==0.6.0
+requests==2.25.1
+six==1.16.0
+snowballstemmer==2.1.0
+Sphinx==4.0.1
+sphinx-markdown-tables==0.0.15
+sphinx-rtd-theme==0.5.2
+sphinx-sitemap==2.2.0
+sphinxcontrib-applehelp==1.0.2
+sphinxcontrib-devhelp==1.0.2
+sphinxcontrib-htmlhelp==1.0.3
+sphinxcontrib-jsmath==1.0.1
+sphinxcontrib-qthelp==1.0.3
+sphinxcontrib-serializinghtml==1.1.4
+typing-extensions==3.10.0.0
+urllib3==1.26.4
+zipp==3.4.1