add version control over build infra

.github/workflows/collab.yml

@@ -52,7 +52,7 @@ jobs:
       - name: Install Build Software
         shell: bash -l {0}
         run: |
-          pip install jupyter-book docutils==0.17.1 quantecon-book-theme sphinx-tojupyter sphinxext-rediraffe sphinx-exercise sphinxcontrib-youtube sphinx-togglebutton arviz
+          pip install jupyter-book==0.15.1 docutils==0.17.1 quantecon-book-theme==0.7.1 sphinx-tojupyter==0.3.0 sphinxext-rediraffe==0.2.7 sphinx-exercise==0.4.1 sphinxcontrib-youtube==1.1.0 sphinx-togglebutton==0.3.1 arviz==0.13.0
       # Build of HTML (Execution Testing)
       - name: Build HTML
         shell: bash -l {0}