Add Puppeteer only workflow

.github/workflows/puppeteer.yml

@@ -0,0 +1,41 @@
+name: Puppeteer tests
+
+# We've experienced quite a lot of instability with the puppeteer setup, notably
+# the fact that it works locally but not in the Github action. Thus, we've removed
+# it from the main integrate workflow, which in turns means we do not have a nice
+# way to try and fix it.
+
+# This workflow only runs the puppeteer tests, and MUST NOT be required as a branch
+# protection. It will nonetheless let us monitor the status of it and make it easier
+# for us to fix the problems once we get to it.
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - "*"
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [18, 20]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+      - uses: actions/cache@v4
+        with:
+          path: .yarn/cache
+          key: yarn-${{ hashFiles('yarn.lock') }}
+      - run: >
+          yarn config set
+          npmScopes.siteimprove.npmAuthToken
+          ${{ secrets.GITHUB_TOKEN }}
+      - run: yarn install --immutable
+      - run: yarn build
+      - run: yarn workspace end-to-end-testing-puppeteer test