There are times when you do not want git to track changes to a versioned file. In these cases you can update the git index so that it assumes the file is unchanged. This will only affect your local repo and it will take affect until you tell git otherwise.
Tell Git to Not Track Changes
You can tell git to not track changes by using
git update-index --assume-unchanged <file>
Tell Git to Track Changes (Again)
And when you want git to track changes again you can use
git update-index --no-assume-unchanged <file>