Add hidden files to package_data


*Originating Project/Creator*
*Affected Component*
*Affected Architectures(s)*
*Related Issue(s)*
*Has Unit Tests (y/n)*
*Builds Without Errors (y/n)*
*Unit Tests Pass (y/n)*
*Documentation Included (y/n)*

Change Description

.gitignore was not being added to the package because the package_data glob pattern was not matching hidden files. Adding it explicitly.

I unfortunately missed that during testing, because I usually use pip install -e ... which uses source files directly.