Feature Request: Add a file filter

[HuakunShen]

Is your feature request related to a problem? Please describe.
Some files pushed to git don't necessarily reflect contributions. For example, package-lock.json.

Describe the solution you'd like
Add a filter to filter out contributions from specific files.

[igbanam]

This already exists.

export _GIT_PATHSPEC=':!pattern'

To see this, checkout man git-quick-stats and scroll to the bottom

git-quick-stats/git-quick-stats.1

Lines 146 to 149 in d33ede9

	You can exclude directories or files from the stats by using pathspec, example:
	.PP
	.B export _GIT_PATHSPEC=':!pattern'
	.PP