No bash in PATH on self-hosted Windows runner

When I initially tried to use `conan-io/setup-conan@v1` I stuck with an error:

```
Error: bash: command not found
```

Turned out that my self-hosted Windows runner doesn't have `bash` visible to run command. I google a bit for such error and found that it can be resolved by adding bash from Git installation, so I added additional step in my workflow file before `setup-conan` action:

```
- name: Add Git Bash to PATH
run: |
echo "C:/Program Files/Git/bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
```

It works, but probably there's more elegant way and can be somehow addressed internally by `conan-io/setup-conan`.
What do you think?

Reproduce the reported `bash: command not found` failure for `conan-io/setup-conan@v1` on a self-hosted Windows runner, then inspect how the action handles the runner environment. Done means the action works without the separate Git Bash PATH step, or clearly documents the required workaround.

Written by the indexing model from the issue text.