Support Composer 2

[mglaman]

  Problem 1
    - civicrm/civicrm-core[5.29.0, ..., 5.31.x-dev] require civicrm/composer-downloads-plugin ^2.0 -> satisfiable by civicrm/composer-downloads-plugin[v2.0.0, v2.1.0, v2.1.1].
    - civicrm/composer-downloads-plugin[v2.0.0, ..., v2.1.1] require composer-plugin-api ^1.1 -> found composer-plugin-api[2.0.0] but it does not match the constraint.
    - Root composer.json requires civicrm/civicrm-core ~5.29 -> satisfiable by civicrm/civicrm-core[5.29.0, ..., 5.31.x-dev].

[mglaman]

This needs manual testing, I thought there was CI attached.

[seamuslee001]

@mglaman My unerstanding from @totten is that there needs to be some re-writing of this plugin because the underlying API within composer has changed from v1 => v2

[mglaman]

Thanks, @seamuslee001, I assumed there would be something which broke. I'll see if I can work on the changes and support v1 and v2 of the API

[mglaman]

Okay, I've added an Actions workflow and running the tests locally.

I'll work on fixing PharHandler where it's getting an incorrect directory for chmod

[mglaman]

Looks like it should be passing, now: https://github.com/mglaman/composer-downloads-plugin/actions/runs/336596453

[seamuslee001]

I've tested this on both a composer2 and composer1 install and have run unit tests with both and confirmed it works, I'm going to merge this and tag a new release

[mglaman]

@seamuslee001 thanks! I'll try it out on my CI runs which install civicrm-core