Re-add pygraphviz as a dependency. (networkx#137)

* Re-add pygraphviz as a dependency.

* Try re-ordering installation in macos job.

.github/workflows/notebooks.yml

@@ -42,7 +42,6 @@ jobs:
     - name: Install dependencies
       run: |
         pip install -U pip
-        pip install -r requirements.txt
 
         if [ "$RUNNER_OS" == "macOS" ]; then
           pip install --config-settings="--global-option=build_ext" \
@@ -51,8 +50,12 @@ jobs:
                       pygraphviz
         elif [ "$RUNNER_OS" == "Linux" ]; then
           pip install pygraphviz
+
         fi
 
+        pip install -r requirements.txt
+        pip list
+
     - name: Lint with precommit
       run: |
         pip install pre-commit

requirements.txt

@@ -1,12 +1,13 @@
 # nx-guides is tested on the development branch of NetworkX
 git+https://github.com/networkx/networkx@main
 
-# Scientific Python (see networkx/requirements/default.txt)
+# Dependencies for running the tutorials
 numpy
 scipy
 matplotlib
 pandas
 ipython!=8.7.0
+pygraphviz
 
 # For testing and site generation
 nbval