feat: add version flag

[laurentsenta]

💣 depends on build-args in docker-container-action. Do not merge this is released and replaced in the current PR.

We want to output the version as a piece of metadata during testing. We will use this metadata during dashboard generation to signal gateways using different versions of the conformance test suite.

Example output: note the version in the dashboard
https://github.com/ipfs/gateway-conformance/actions/runs/5761510674/attempts/1#summary-15619660151

Supports #123

• Introduce a version flag in the CLI
• Update the workflows to release with the correct version flag
• Output the version as a piece of metadata during test execution, if possible, related discussion in go project
• Output version during dashboard generation

Note

This PR introduces metadata output, which we'll reuse for other pieces of data. This allows us to add more details to our tests, like a gateway checker id, specs id, etc.
For now, we're using a special log format --- META: .... This is a temporary workaround for the lack of metadata, which is being worked on in golang/go. We'll replace these with the official API when it's released.

[laurentsenta]

TIL: if you push the main branch to reset a branch, it'll close the associated PR

[galargh]

What do you think about sourcing the metadata from git context? Similarly to what you already do in the Makefile. To me it feels more reliable - less moving parts.

Suggested change

	ARG VERSION=dev
	RUN go build -ldflags="-X github.com/ipfs/gateway-conformance/tooling.Version=${VERSION}" -o ./gateway-conformance ./cmd/gateway-conformance
	RUN export TAG="$(git tag --points-at HEAD | sort -V | tail -n-1)" && \
	export COMMIT="$(git rev-parse HEAD --short)" && \
	export DIRTY_SUFFIX="$(test -n "`git status --porcelain`" && echo "-dirty" || true)" && \
	export VERSION="${TAG:-$COMMIT$DIRTY_SUFFIX}" && \
	go build -ldflags="-X github.com/ipfs/gateway-conformance/tooling.Version=${VERSION}" -o ./gateway-conformance ./cmd/gateway-conformance

For that to work, we'd only have to make sure the tags are fetched when we're building the docker image.

Also, one thing I noticed, we create tags slightly incorrectly. If you inspect v0, v0.3 and v0.3.0 now, you'll notice that v0 and v0.3 are on a different commit than v0.3.0. We should look into why that is - might need a fix in changelog based release action, I'll try to get to it today.

[galargh]

ipdxco/changelog-driven-release#9 <- I think this might be the fix for the tag mismatch. I'll test it later today.

[laurentsenta]

I think that'd create coupling / break single responsibility principle: instead of having a single argument, the docker build would depend on many side-effects to succeed (git binary, .git folder is around, repo is fetch'd as expected, etc).