Trim temp directory from path when reporting errors in source code

[thomashoneyman]

When a failure happens in the publish pipeline due to a problem with a package's source code, we report the bad files using their full filepath as we have it at the time of the error. For example:

• /tmp/tmp-2519-YapUyZ5Cpp6j/purescript-punycode/src/Main.purs as seen in this publish failure.

We should trim the temporary directory because it's just noise. The directory will be gone by the time we have a chance to go look at the server filesystem anyways (or, in the case of GitHub Actions, it'll most certainly be gone by the time the workflow completes). This error would then report purescript-punycode/src/Main.purs as the path.