Bug#1002903: python3-openpyxl: no longer depends on jdcal

[Nis Martensen]

Package: python3-openpyxl
Version: 3.0.9-1
Severity: minor
X-Debbugs-Cc: nis.martensen at web.de

Since version 3.0.7 openpyxl no longer depends on jdcal, so the
dependency of the python3-openpyxl package on python3-jdcal can be dropped.

Not sure if jdcal has any other reverse dependencies in debian; it may
make sense to remove it from debian if there aren't any.