Migrate giant to github actions

.github/workflows/build.yml

@@ -0,0 +1,53 @@
+# Find full documentation here https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
+name: CI
+
+on:
+  # Manual invocation.
+  workflow_dispatch:
+
+  push:
+
+jobs:
+  CI:
+    runs-on: ubuntu-latest
+
+    # See https://docs.github.com/en/actions/security-guides/automatic-token-authentication#permissions-for-the-github_token
+    permissions:
+      # required by aws-actions/configure-aws-credentials
+      id-token: write
+      contents: read
+    steps:
+      - uses: actions/checkout@v4
+
+      # Setup AWS credentials to enable uploading to S3 for Riff-Raff.
+      # See https://github.com/aws-actions/configure-aws-credentials
+      - uses: aws-actions/configure-aws-credentials@v4
+        name: setup-riffraff-credentials
+        with:
+          role-to-assume: ${{ secrets.GU_RIFF_RAFF_ROLE_ARN }}
+          aws-region: eu-west-1
+
+      # Setup Node, checking common Node config files to determine the version of Node to use.
+      # Configuring caching is also recommended.
+      # See https://github.com/guardian/actions-setup-node
+      - name: Setup Node
+        uses: actions/setup-node@v3
+        with:
+          node-version-file: .nvmrc
+
+      # Configuring caching is also recommended.
+      # See https://github.com/actions/setup-java
+      - name: Setup Java 8
+        uses: actions/setup-java@v3
+        with:
+          java-version: '11'
+          distribution: 'adopt'
+
+      # 1. Seed the build number with last number from TeamCity.
+      #    Update `LAST_TEAMCITY_BUILD` as needed or remove entirely if changing Riff-Raff project name.
+      # See https://github.com/github/scripts-to-rule-them-all
+      - name: Run script/teamcity
+        run: |
+          LAST_TEAMCITY_BUILD=5000
+          export GITHUB_RUN_NUMBER=$(( $GITHUB_RUN_NUMBER + $LAST_TEAMCITY_BUILD ))
+          ./scripts/teamcity.sh

scripts/teamcity.sh

@@ -21,7 +21,10 @@ popd
 cp -r frontend/build/* backend/public
 # Replace the symbolic link we use in dev with the actual file.
 # On Teamcity the JDeb build doesn't seem to follow the symbolic link while packaging, weirdly
-cp frontend/node_modules/pdfjs-dist/build/pdf.worker.min.js backend/public/third-party/pdf.worker.min.js
+# NOTE: On Github actions this seems to work, and in fact it will complain if you try and run the below line
+# because it thinks that the two files are the same. So  could be removed at some point but let's leave it for
+# a bit in case e.g. github actions custom runners have similar issues
+#cp frontend/node_modules/pdfjs-dist/build/pdf.worker.min.js backend/public/third-party/pdf.worker.min.js
 
 #Use java 11
 export JAVA_HOME=/usr/lib/jvm/java-11-amazon-corretto