Add Support for Files Manifest Package Paths

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**Is your feature request related to a problem? Please describe.**
Right now, the package paths for manifest releaser is required to be a directory. However, I've got several "single file" components that live in a single directory. It's frustrating that this is referred to as a _path_ and not a _directory_, took a lot of reading of the source code to understand this limitation.

**Describe the solution you'd like**
I would like the package paths in the manifest releaser to support individual files.

**Describe alternatives you've considered**
The only alternative is to split the single file components up into separate directories, which seems a little heavy handed. A directory with 1 file in it is overkill.

**Additional context**
N/A