Add pinecone demo container image (#2710)

This pull request adds the configuration and CI steps to build and
publish a container wrapping the `dendrite-demo-pinecone` command as
well as fixes a sentence structure issue in the pull request template.

As this does not touch any go source code no tests have been added

### Pull Request Checklist

<!-- Please read docs/CONTRIBUTING.md before submitting your pull
request -->

* [x] I have added tests for PR _or_ I have justified why this PR
doesn't need tests.
* [x] Pull request includes a [sign
off](https://github.com/matrix-org/dendrite/blob/main/docs/CONTRIBUTING.md#sign-off)

Signed-off-by: networkException <git@nwex.de> (by private sign-off)
Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

2 files changed, 61 insertions, 1 deletions

diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 9bfb0166..e0b82e2a 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -2,7 +2,7 @@
 
 <!-- Please read docs/CONTRIBUTING.md before submitting your pull request -->
 
-* [ ] I have added added tests for PR _or_ I have justified why this PR doesn't need tests.
+* [ ] I have added tests for PR _or_ I have justified why this PR doesn't need tests.
 * [ ] Pull request includes a [sign off](https://github.com/matrix-org/dendrite/blob/main/docs/CONTRIBUTING.md#sign-off)
 
 Signed-off-by: `Your Name <your@email.example.org>`
diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 64258792..b4e24e52 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -137,3 +137,63 @@ jobs:
             ${{ env.DOCKER_NAMESPACE }}/dendrite-polylith:${{ env.RELEASE_VERSION }}
             ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-polylith:latest
             ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-polylith:${{ env.RELEASE_VERSION }}
+
+  demo-pinecone:
+    name: Pinecone demo image
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Get release tag
+        if: github.event_name == 'release' # Only for GitHub releases
+        run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Login to Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ env.DOCKER_HUB_USER }}
+          password: ${{ secrets.DOCKER_TOKEN }}
+      - name: Login to GitHub Containers
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build main pinecone demo image
+        if: github.ref_name == 'main'
+        id: docker_build_demo_pinecone
+        uses: docker/build-push-action@v2
+        with:
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          context: .
+          file: ./build/docker/Dockerfile.demo-pinecone
+          platforms: ${{ env.PLATFORMS }}
+          push: true
+          tags: |
+            ${{ env.DOCKER_NAMESPACE }}/dendrite-demo-pinecone:${{ github.ref_name }}
+            ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-demo-pinecone:${{ github.ref_name }}
+
+      - name: Build release pinecone demo image
+        if: github.event_name == 'release' # Only for GitHub releases
+        id: docker_build_demo_pinecone_release
+        uses: docker/build-push-action@v2
+        with:
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          context: .
+          file: ./build/docker/Dockerfile.demo-pinecone
+          platforms: ${{ env.PLATFORMS }}
+          push: true
+          tags: |
+            ${{ env.DOCKER_NAMESPACE }}/dendrite-demo-pinecone:latest
+            ${{ env.DOCKER_NAMESPACE }}/dendrite-demo-pinecone:${{ env.RELEASE_VERSION }}
+            ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-demo-pinecone:latest
+            ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-demo-pinecone:${{ env.RELEASE_VERSION }}