Delete gh-pages.yml

This shouldn’t exist, let alone make commits to the repo. Kind of annoyed this is here and ran today.

.github/workflows/gh-pages.yml

@@ -1,18 +0,0 @@
-name: GitHub Pages
-on:
-  push:
-    branches:
-      - main
-
-jobs:
-  build:
-    name: Deploy docs
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout master
-        uses: actions/checkout@v1
-
-      - name: Deploy docs
-        uses: mhausenblas/mkdocs-deploy-gh-pages@1.14
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}