Add `make release` target to the Makefile

In order to have a common release process, we want to add a make release target to the Makefile, to work like in other repositories.

Compare the release process in the docs.

changed milestone to %1.0-alpha5 — Capable Capybara

added P2 label

@eigenwijsje is this also something we can assign to @chrizz?

Yes, please and thanks!

assigned to @chrizz

changed milestone to %1.0-alpha4 — Raving Raccoon

changed milestone to %1.0-alpha5 — Capable Capybara

added size:s label

added time estimate of 2h

assigned to @eigenwijsje and unassigned @chrizz

added To Do label

added Doing label and removed To Do label

closed with commit 1a3a916d

removed Doing label

added 25m of time spent

added Cycle [3/24] label