Reusable workflows

[zakkak]

• Allows the whole matrix to run under a single CI run while making the base workflow reusable by other branches so that we can stop replicating CI pipelines in release branches. This has the following benefits:

  1. The whole matrix runs a lot faster (~4h for all combinations instead of ~2h per combination in some cases)

     Before:
     

     After:
     

  2. It's much easier to understand what fails in the whole matrix by inspecting a single page (it used to be 8)

  3. We can now test the workflow in PRs that affect it

• Adds wrappers for workflow_dispatch, so that we can still run custom jobs with gh workflow run...
• Makes artifacts unique per reusable workflow inputs. This is necessary since when using reusable workflows and calling a reusable workflow multiple times from the same caller workflow will result in artifact-name collisions.

Special thanks to @gvre for:

• Making me aware of the GA of reusable workflows
• Reading my rants while I was exploring the uncharted waters of reusable workflows
• Helping me overcome some of the obstacles I faced while transitioning our pipeline from workflow_dispatch to workflow_call

[jerboaa]

OK, but I'm not much use as a reviewer for gh workflow files ;-)

[zakkak]

OK, but I'm not much use as a reviewer for gh workflow files ;-)

I mostly include you and Karm in those to make sure you are aware of the changes and to spot potential high level issues. I don't expect you to parse the yaml file :)