[release/1.2.x] Onboard to CRT

[claire-labry]

Onboard Nomad OSS [release/1.2.x] to Common Release Tooling

There are a few important changes to call out in this PR:

GitHub Actions is being used as the CI provider to build the go binary artifacts and linux packages. This logic lives in .github/workflows/build.yml and workflow runs are available under https://github.com/hashicorp/nomad/actions.
Artifact builds will continue to run on PR's and merges to main. This behavior can be changed by updating the on: logic in the .github/workflows/build.yml file.

The .release/ci.hcl file contains some metadata for our release service. The only part you'll likely ever need to change is the release_branches array -- when you want to release off of a new release branch, update this value to the release branch name and be sure to update the branches array in .github/workflows/build.yml to the same value. This should be set to either main, the release branch that we'll be releasing off of (once release branches are adopted), or a test branch that you are working off of if you need to validate every part of the pipeline before merging.

• Clean up this branch before merging [slack ID and branch naming from onboarding tests]

This PR includes the Generate Static Assets workflow-- this workflow generates the static files that are needed for release day. It commits any generated static files that were made into the release branch. These files will either be committed (if files are generated) or no files will be pushed based on the changes that are pushed up.

• generate-static-assets workflow run passed here:

• This workflow then kicks off the build workflow which passed here:

• You can see here that there were no files were updated (committed).

[kpenfound]

Instead of using a workflow dispatch here, we could use the builtin workflow_run.
See docs here: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#onworkflow_runbranchesbranches-ignore
and here: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_run

So the opening part of the build.yml would look like:

on:
  workflow_run:
    workflows: [Generate Static Assets]
    types:
      - completed

[kpenfound]

Nevermind, this workflow would have to be on the default branch!

[sarahethompson]

@kpenfound - we tried this 😢 but unfortunately it only triggers on the default branch and we want this to run on commits to the release branches

[kpenfound]

🚀

[github-actions]

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