Consider updating .gitattributes

[Gramps]

Hey there! You may want to consider updating your .gitattributes file so users only download the asset itself; currently it downloads the full repo. A simple version would be something like:

# Normalize line endings for all files that Git considers text files.
* text=auto eol=lf

# Only include the addons folder when downloading from the Asset Library.
/**        export-ignore
/addons    !export-ignore
/addons/** !export-ignore