Add synapse version as Docker container label

[thebalaa]

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
  • End with either a period (.) or an exclamation mark (!).
  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Pull request includes a sign off
• Code style is correct
  (run the linters)

Signed-off-by: Mo Balaa mo@fractalnetworks.co

[clokep]

Please add a changelog file.

[thebalaa]

@clokep @DMRobertson added changelog and changed label to org.opencontainers.image.version

[DMRobertson]

Thank you!

changelog added

[thebalaa]

@clokep any ideas why CI is failing for this?

[thebalaa]

@DMRobertson didn't work, got any suggestions on how we can easily test the pipeline?

           "OnBuild": null,
            "Labels": {
                "gitsha1": "96529c42368a6153a92330c3f03be5b02ce4653c",
                "org.opencontainers.image.documentation": "https://github.com/matrix-org/synapse/blob/master/docker/README.md",
                "org.opencontainers.image.licenses": "Apache-2.0",
                "org.opencontainers.image.source": "https://github.com/matrix-org/synapse.git",
                "org.opencontainers.image.url": "https://matrix.org/docs/projects/server/synapse",
                "org.opencontainers.image.version": ""
            }
        },
        ```

[DMRobertson]

@thebalaa see https://github.com/matrix-org/synapse/actions/runs/5671200867/job/15367813605

Run echo "SYNAPSE_VERSION=$(grep "^version" pyproject.toml | sed -E 's/version\s*=\s*"["]/\1/')" >> $GITHUB_ENV
echo "SYNAPSE_VERSION=$(grep "^version" pyproject.toml | sed -E 's/version\s*=\s*"["]/\1/')" >> $GITHUB_ENV
shell: /usr/bin/bash -e {0}
grep: pyproject.toml: No such file or directory

We need to checkout the repository before running this comment. (It looks like it gets checked out later in "Run docker/build-push-action@v4"))