🩹 Fix path in artifact name for windows upload

[s-weigand]

This fixes an issue where the path is part of the artifact name with artifacts uploaded from windows. The cause was that path.Base only works with / while filepath.Glob returns paths with \ on windows.

Package path implements utility routines for manipulating slash-separated paths.

vs.

Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths.

I also applied this change to writeChecksums since having the original folder structure in the checksum file does not make sense when comparing it against the file on the release page.

[s-weigand]

~Looks like the CI is failing because the drone CI ARM runner did run out of space 🤷‍♀️~ Turns out it was a bad pipeline fixed in this PR