fix: remove checkout-and-build

This is to replace it with the Gatsby Build check, includes changes to documentation and diagram of workflows

.github/workflows/release.yml

@@ -10,35 +10,6 @@ env:
   BOT_EMAIL: [email protected]
 
 jobs:
-  checkout-and-build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repo
-        uses: actions/checkout@v2
-
-      - name: Setup Node.js
-        uses: actions/setup-node@v1
-        with:
-          node-version: 12
-
-      - name: Get yarn cache directory path
-        id: yarn-cache-dir-path
-        run: echo "::set-output name=dir::$(yarn cache dir)"
-
-      - uses: actions/cache@v2
-        id: yarn-cache
-        with:
-          path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
-          key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-yarn-
-
-      - name: Install dependencies
-        run: yarn install --frozen-lockfile
-
-      - name: Gatsby Build
-        run: yarn run build:production
-
   generate-third-party-notices:
     runs-on: ubuntu-latest
     needs: checkout-and-build