Fix banner date logic
Fix banner date logic

Months in `new Date(y, m, d)` are 0-based, just to be awkward

rsalmaso/wagtail,zerolab/wagtail,rsalmaso/wagtail,wagtail/wagtail,wagtail/wagtail,thenewguy/wagtail,rsalmaso/wagtail,wagtail/wagtail,zerolab/wagtail,thenewguy/wagtail,wagtail/wagtail,rsalmaso/wagtail,wagtail/wagtail,rsalmaso/wagtail,thenewguy/wagtail,zerolab/wagtail,thenewguy/wagtail,zerolab/wagtail,thenewguy/wagtail,zerolab/wagtail