bump from imaplib2 v2.51 to v2.52
bump from imaplib2 v2.51 to v2.52

Thanks-to: Sébastien Gross <seb•ɑƬ•chezwam•ɖɵʈ•org>
Signed-off-by: Nicolas Sebrecht <347709267ddd1958560c4c317ea3fd613f10a719@laposte.net>

frioux/offlineimap,frioux/offlineimap