Update set-output to use GITHUB_OUTPUT file

[JP-Dhabolt]

Resolves #205

Summary of changes

Updates how output is being set to remove warnings and prevent breakage once Github removes support for the set-output echo statements.

Do any of the followings changes break current behaviour or configuration?

• NO

How changes have been tested

• Tested locally by setting the environment variable to /dev/stdout to see the correct output.
• test.yml workflow should validate the functionality by executing this changed action.

List any unknowns

• Should not be any unknowns, as this is following Github's documentation on how to set outputs as of 2022-10-11

[sbe-arg]

Thanks for doing this, just a simple comment otherwise looks god.

[Sandra-headscape]

Hi, this seems ready to go? I'd like to get this into my workflow without using the fork - thanks (:

update 18Nov2022: am currently using 1.52.0, but upon checking realised this wasn't released as a new version as the build failed - https://github.com/anothrNick/github-tag-action/actions/runs/3372412451/jobs/5595804270

did i miss something? thanks (: