Use a matrix job to deploy our clusters

[yuvipanda]

For sure! I was going to suggest using something like this action to set a conditional on the paths changed https://github.com/dorny/paths-filter
So we maintain the same behaviour of not doing a deploy when nothing's changed, but we can consolidate into a single workflow file and new clusters can just be added to the matrix element list.

Originally posted by @sgibson91 in #569 (comment)

[sgibson91]

The current behaviour is that if any of the below filepaths change, even if a .cluster.yaml file doesn't change, we still deploy right?

https://github.com/2i2c-org/pilot-hubs/blob/845c961b3ee95a9f919a7d4c2086fdc8901baa5a/.github/workflows/deploy-2i2c.yaml#L7-L11

I am testing the workflow over here https://github.com/sgibson91/test-pathfile-conds-gh-actions

[choldgraf]

This sounds like a great idea to me - would definitely improve our DRY for these deploy auto-actions