Add concurrancy to Github CI action

[adamjtaylor]

Currently, the lint, validate and convert action runs when a commit is made into a PR. If two commits are made in close sequence then two actions can be launched, when only the latter needs to complete.

This can cause the second action to fail in the commit phase of the conversion job as it seems that there are unstashed changes from when the first job overwrote the JSON-LD.

We can use GitHub actions concurrency to cancel previously started jobs to ensure that this does not occur

https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#concurrency

[adamjtaylor]

We are seeing concurrency issues in #245, so we should prioritize this for the July sprint

[adamjtaylor]

@afwillia has implemented a similar concurrancy fix here: https://github.com/Sage-Bionetworks/data-models/blob/bd1daaecf34ac25a4dc5ae987ce041d72d706ae2/.github/workflows/dcc_config_repo_dispatch.yml#L29C1-L39C27