$WEEKSTART comparison fails on non-English locales.

[AndySun25]

We have had a few devs at our group being unable to use git-standup on Mondays due to the hardcoded comparison for $WEEKSTART. I've forked the repo and made a quick fix for internal use and was wondering if there may be interest in implementing it upstream as well.

gimi-org/git-standup@c74aa71

I'm fairly new to writing bash scripts with cross-platform compatibility so any sort of feedback would be appreciated. (And yes there is a typo in that commit but that has since been fixed)

[devoth]

This still seems to be an issue for me, every monday I need to remember to run git standup -d3 instead of git standup otherwise it tells me I did nothing last day ;)