Fix action.yml: Bump to 3.0.3

[yudgnahk]

I got error panic: gha-find-replace: expected with.replace to be a string when I try to replace with an empty string.
I saw that you have already fixed it, but your action.yml version is not updated.

[jacobtomlinson]

Thanks for spotting this. Unfortunately we need to cut another release to resolve this, so I'm going to bump to 3.0.3 instead and git a new release.