Add matrix input to Github Action

[mathias-luedtke]

jobs:
  industrial_ci:
    strategy:
      matrix:
        ROS_DISTRO: [melodic]
        ROS_REPO: [testing, main]
    runs-on: ubuntu-latest
    steps:
      - ...
      - uses: 'ros-industrial/industrial_ci@master'
        with:
          matrix: ${{toJSON(matrix)}}

$ can be escaped with $$.
Without escaping, the variable substitution will happen immediately.

[mathias-luedtke]

Not sure, if matrix is the right name. config might be better.

[gavanderhoorn]

$ can be escaped with $$.
Without escaping, the variable substitution will happen immediately.

can or must?

The latter would be unfortunate.

[mathias-luedtke]

$ can be escaped with $$.
Without escaping, the variable substitution will happen immediately.

can or must?

Depends ;)
It works the same as for Gitlab CI.
For BEFORE/AFTER_* scripts you must escape it, for configuration variable early substitution should be fine.

I could rewrite it to not support substitution at all, but then there might be no way to have substitution for Github Actions.

[mathias-luedtke]

I just renamed the input to config and decided to not change the template yet (to be discussed in #590).