Proper fix for graphviz (pytorch#943)

Summary:
Third PR to figure out how to generate images by graphviz within spinx

- Step 1 Add a debug workflow to figure out the proper solution
  - Shown no warning about missing `dot` command (https://github.com/pytorch/data/actions/runs/3897152397/jobs/6654521346#step:6:399)
- Step 2 remove debug workflow and add `apt-get install graphviz` to make sure the CI machine has `graphviz` and `dot` installed and exposed to cml.

Pull Request resolved: pytorch#943

Reviewed By: wenleix, NivekT

Differential Revision: D42463417

Pulled By: ejguan

fbshipit-source-id: f7e3019ba8d86c85e15330c10dd2b6e4362f6c3b

.github/workflows/_build_test_upload.yml

@@ -487,6 +487,7 @@ jobs:
       - name: Build the docset
         run: |
           cd ./docs
+          sudo apt-get install -y graphviz
           pip3 install -r requirements.txt
           make html
           cd ..

docs/requirements.txt

@@ -3,5 +3,4 @@ sphinx
 # PyTorch Theme
 -e git+https://github.com/pytorch/pytorch_sphinx_theme.git#egg=pytorch_sphinx_theme
 # For Graph Visualization
-pydot
 graphviz