Allow reading of `cover.out`

[wmcnamee-coreweave]

I'm using other things to run my tests, can this action just read cover.out ?

[wmcnamee-coreweave]

I'm coming back to this... and still wanting this feature 😅

I'm using fgrosse/go-coverage-report for now, but it doesn't have a way to fail if coverage decreases. I suppose I could use something else to parse cover.out.

[gwatts]

@wmcnamee-coreweave thanks for bumping it; still hoping to give this project some attention again soon!