maint: add label type:dependencies to maintenance category for release notes

[JamieDanielson]

Which problem is this PR solving?

• auto-generated release notes put all dependency bumps into "other changes"

Short description of the changes

• add label type:dependencies to maintenance category for release notes

How to verify that this has the expected result

next time we auto-generate notes for a release that includes a dependabot update, it should show up in the maintenance category