git-latexdiff does require bash, hence we can't substitute /bin/sh as
the shell bang. Also, the previous regular expression wasn't matching
the actual shebang.
Fixes#8.
The previous version was hardcoded in the script, and not linked to Git
tags. It has been 1.0 since Dec 24 15:35:32 2012, before the 1.0.0 tag
actually.