Set env variables

[Sam2much96]

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• Is this related to the actions-rs Actions?
  If you think it's a problem related to Github Actions in general, use GitHub Community forum instead: https://github.dijk.eu.orgmunity
• You've read the Contributing section about feature requests: https://github.com/actions-rs/.github/blob/master/CONTRIBUTING.md#feature-requests
• Is this something you can debug and fix? Send a pull request! Bug fixes and documentation fixes are welcome.

Motivation

Describe your idea, motivation, and how Rust community could benefit from this feature.
To implement compiler environment variables without the using a config.toml file

Workflow example

If applicable, create an example on how this feature will look in the workflow yaml file

• name: Build for Armv7
  uses: actions-rs/cargo@v1.0.1
  with:
  command: build
  args: --target armv7-unknown-linux-gnueabihf
  env: |
  OPENSSL: ${{ github.workspace }}/openssl_android #arm
  OPENSSL_DIR: ${{ github.workspace }}/openssl_android

Additional context

Add any additional information about this feature; that includes links to the related tools, alternative implementations, blog posts and so on