Setup ecm-distro-tools GitHub Action

[brooksn]

This PR introduces the GitHub action for this repository, named Setup ecm-distro-tools. It simply downloads the assets from a named release, and puts them in the PATH. Inspired by hashicorp/setup-terraform.

GitHub allows any repository to publish only one action. Because users may have a variety of cases for ecm-distro-tools functionality in their workflows, this action aims to be as flexible as possible to cover future needs.

The action will not be published to the Marketplace.

usage:

name: Main
on: push
jobs:
  main:
    runs-on: ubuntu-latest
    steps:
    - name: setup ecm-distro-tools
      uses: rancher/ecm-distro-tools
      with:
        version: v0.23.0
      env:
        GH_TOKEN: ${{ github.token }}
    - name: release notes
      run: gen_release_notes -h

Providing a GitHub token is recommended to avoid rate limiting, but not required.

[brooksn]

The user can specify which version of the install script to use like this:

uses: rancher/[email protected]

uses: rancher/ecm-distro-tools@d3d56ddf759357299e72d779bba224f42e2852f2

uses: rancher/ecm-distro-tools@v1

Note that the version of the install script is separate from the version of the binaries. Alternately, we could explore using omitting the version argument and using the same version for both with this form.