bin/contact-maintainers: Provide mail template for LTS updates of minor issues.
As the LTS team also sometimes works on packages with only <no-dsa> issues open, it might be good to also inform package maintainers about this.
This adds an ltsp-update-planned-minor.txt mail template plus a command line option (--minor) that LTS front desk people can use if they choose to add a package to dla-needed.txt with <no-dsa> issues only.
Edited by Mike Gabriel