MAINT: Update master to main (#149)

Author: mmcky

.github/workflows/cache.yml

@@ -2,7 +2,7 @@ name: Build Cache [using jupyter-book]
 on:
   push:
     branches:
-      - master
+      - main
 jobs:
   tests:
     runs-on: ubuntu-latest

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
         uses: dawidd6/action-download-artifact@v2
         with:
           workflow: cache.yml
-          branch: master
+          branch: main
           name: build-cache
           path: _build
       # Build Assets (Download Notebooks and PDF via LaTeX)
@@ -61,7 +61,7 @@ jobs:
         uses: nwtgck/[email protected]
         with:
           publish-dir: '_build/html/'
-          production-branch: master
+          production-branch: main
           github-token: ${{ secrets.GITHUB_TOKEN }}
           deploy-message: "Preview Deploy from GitHub Actions"
         env:

.github/workflows/publish.yml

@@ -40,7 +40,7 @@ jobs:
       #   uses: dawidd6/action-download-artifact@v2
       #   with:
       #     workflow: cache.yml
-      #     branch: master
+      #     branch: main
       #     name: build-cache
       #     path: _build
       # Build Assets (Download Notebooks, PDF via LaTeX)
@@ -86,7 +86,7 @@ jobs:
           cp _build/jupyter/*.ipynb _build/lecture-python-programming.notebooks
           ls -a _build/lecture-python-programming.notebooks
       - name: Commit latest notebooks to lecture-python-programming.notebooks
-        uses: cpina/github-action-push-to-another-repository@master
+        uses: cpina/github-action-push-to-another-repository@main
         env:
           API_TOKEN_GITHUB: ${{ secrets.QUANTECON_SERVICES_PAT }}
         with: