add docker hub instructions to release template (#260)

Author: antondlr

.github/workflows/release.yml

@@ -175,8 +175,20 @@ jobs:
 
           - [ ] Merge `unstable` -> `stable`.
           - [ ] Ensure docker images are published to `sigp` namespace (instructions below)
+          - [ ] Ensure docker images are published to `sigp` namespace (instructions below)
           - [ ] Prepare Discord post.
 
+          Someone with appropriate access rights should run these commands:
+          0. sanity check: did the `docker` workflow complete correctly, are the images published under the `sigmaprime` namespace? 
+             see: https://hub.docker.com/r/${{ env.DOCKER_USERNAME }}/siren/tags?name=${{ env.VERSION }} and https://hub.docker.com/r/${{ env.DOCKER_USERNAME }}/siren/tags?name=latest
+          1. publish `latest`: 
+             `docker manifest create sigp/siren:latest --amend sigmaprime/siren:latest-amd64 --amend sigmaprime/siren:latest-arm64`
+             `docker manifest push sigp/siren:latest`
+          2. publish `${{ env.VERSION }}`:
+             `docker manifest create sigp/siren:${{ env.VERSION }} --amend sigmaprime/siren:${{ env.VERSION }}-amd64 --amend sigmaprime/siren:${{ env.VERSION }}-arm64`
+             `docker manifest push sigp/siren:${{ env.VERSION }}`
+          3. verify: https://hub.docker.com/r/siren/siren/tags?name=${{ env.VERSION }} and https://hub.docker.com/r/sigp/siren/tags?name=latest
+
           ## Summary
 
 
@@ -200,21 +212,9 @@ jobs:
 
           ${{ steps.changelog.outputs.CHANGELOG }}
 
-          ## Binaries
-
-          [See pre-built binaries documentation.](https://lighthouse-book.sigmaprime.io/installation-binaries.html)
-
-          The binaries are signed with Sigma Prime's PGP key: `15E66D941F697E28F49381F426416DC3F30674B0`
+          ## Docker Hub
+          https://hub.docker.com/r/sigp/siren/tags?name=${{ env.VERSION }}
 
-          | System | Architecture | Binary | PGP Signature |
-          |:---:|:---:|:---:|:---|
-          | <img src="https://simpleicons.org/icons/apple.svg" style="width: 32px;"/> | x86_64 | [siren-${{ env.VERSION }}-x86_64-apple-darwin.zip](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-x86_64-apple-darwin.zip) | [PGP Signature](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-x86_64-apple-darwin.zip.asc) |
-          | <img src="https://simpleicons.org/icons/linux.svg" style="width: 32px;"/> | x86_64 | [siren-${{ env.VERSION }}-x86_64-unknown-linux-gnu.zip](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-x86_64-unknown-linux-gnu.zip) | [PGP Signature](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-x86_64-unknown-linux-gnu.zip.asc) |
-          | <img src="https://simpleicons.org/icons/raspberrypi.svg" style="width: 32px;"/> | aarch64 | [siren-${{ env.VERSION }}-aarch64-unknown-linux-gnu.zip](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-aarch64-unknown-linux-gnu.zip) | [PGP Signature](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-aarch64-unknown-linux-gnu.zip.asc) |
-          | <img src="https://simpleicons.org/icons/windows.svg" style="width: 32px;"/> | x86_64 | [siren-${{ env.VERSION }}-x86_64-windows.zip](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-x86_64-windows.zip) | [PGP Signature](https://github.com/${{ env.REPO_NAME }}/releases/download/${{ env.VERSION }}/siren-${{ env.VERSION }}-x86_64-windows.zip.asc) |
-          | | | | |
-          | **System** | **Option** | - | **Resource** |
-          | <img src="https://simpleicons.org/icons/docker.svg" style="width: 32px;"/> | Docker | [${{ env.VERSION }}](https://hub.docker.com/r/${{ env.IMAGE_NAME }}/tags?page=1&ordering=last_updated&name=${{ env.VERSION }}) | [${{ env.IMAGE_NAME }}](https://hub.docker.com/r/${{ env.IMAGE_NAME }}) |
           ENDBODY
           )
           tag_name="${{ env.VERSION }}"