Delete create-codespaces-prebuild.yml (#67015)

* Delete create-codespaces-prebuild.yml

* Remove reference to the prebuild action and link to the codespaces doc instead.
Co-authored-by: NEric Erhardt <eric.erhardt@microsoft.com>

.github/workflows/create-codespaces-prebuild.yml

-name: Create Codespaces Prebuild
-on:
-  schedule:
-    # Run at 06:00 am UTC every day
-    - cron:  '0 6 * * *'
-  workflow_dispatch:
-jobs:
-  createPrebuild:
-    # Only run in the main repository since it will fail in forks
-    if: github.repository == 'dotnet/runtime'
-    permissions:
-      contents: write
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: github/codespaces-precache@v1-stable
-        with:
-          regions: WestUs2 EastUs WestEurope
-          sku_name: premiumLinux
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

docs/workflow/Codespaces.md

@@ -24,8 +24,7 @@ The Codespaces configuration is spread across the following places:
     - `devcontainer.json` file configures the codespace and mostly has VS Code settings
     - The Dockerfile used to create the image
     - The `scripts` folder contains any scripts that are executed during the creation of the codespace. This has the build command that builds the entire repo for prebuilds.
-2. The GitHub Action can be configured at [create-codespaces-prebuild](../../.github/workflows/create-codespaces-prebuild.yml)
-    - This contains when the Action is run, what regions we build prebuilds for, and what size machines
+2. The GitHub Action can be configured by following the instructions at https://docs.github.com/codespaces/prebuilding-your-codespaces/configuring-prebuilds.
 
 To test out changes to the `.devcontainer` files, you can follow the process in [Applying changes to your configuration](https://docs.github.com/codespaces/customizing-your-codespace/configuring-codespaces-for-your-project#applying-changes-to-your-configuration) docs. This allows you to rebuild the Codespace privately before creating a PR.