Upload-artifact: Use environment variable in file names

[NPellet]

Describe the bug
Actually it's maybe more of a feature request. It would be very convenient if environment variables could be used to set the path of the artifacts

Version

• [ ] V1
• [x] V2

Environment

• [ ] self-hosted
• [x] Linux
• [ ] Windows
• [ ] Mac

How to reproduce
Consider the following (non reproducible) action exemple:

    - run: echo "::set-env name=MY_VAR::6"
    - name: Save artifact
      uses: actions/upload-artifact@v2
      with:
        name: Artifact_${MY_VAR}
        path: /path/to/file_${MY_VAR}.extension

[Margen67]

Did you try using ${{ env.MY_VAR }} like in the readme? https://github.com/actions/upload-artifact#environment-variables-and-tilde-expansion

[NPellet]

uh. Not sure how I missed that. Was missing the env.

Sorry for having wasted your time :(