At the time of this writing, Go does not yet have support for
internationalized locales for dates, if you create a month.yaml in your data/
folder with a content like shown below. It will work.
1: "janvier"
2: "février"
3: "mars"
4: "avril"
5: "mai"
6: "juin"
7: "juillet"
8: "août"
9: "septembre"
10: "octobre"
11: "novembre"
12: "décembre"