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

changed milestone to %1.0-alpha4 — Raving Raccoon

assigned to @martina

changed milestone to %1.0-alpha5 — Capable Capybara

added size:s label

added time estimate of 6h

added To Do label

added Cycle [3/24] label

mentioned in commit 790aa873

added 30m of time spent

removed To Do label

added Doing label

mentioned in commit 41dd2164

added 30m of time spent

removed Doing label

added To Do label

removed To Do label

added Doing label

added 10m of time spent

removed Doing label

closed