Increment major one step at a time

[leoarnold]

I am working on a project which has not been updated for quite some time. We added Depfu just recently and it offers me updates like jquery from v1 to v3 or jsdom from v4 to v16 - both kinda daring.

I think it would be nice to have the option to increment the major one step at a time, e.g. Depfu would open a PR for the latest jquery v2 version - and only when that has been dealt with and merged, offer the v3.