create craft post release craft

[marandaneto]

add Unreleased back to the (changelog)
append -SNAPSHOT to versionName (gradle.properties)

should the post release script bump the buildVersionCode?
https://github.com/getsentry/sentry-java/blob/main/scripts/bump-version.sh#L15-L19

as the versionName will have the next version-SNAPSHOT, it'd make sense that the buildVersionCode is already the correct one.

[marandaneto]

check if craft is creating a temp. file called gradle.propertiese

[iker-barriocanal]

Creation of gradle.propertiese is addressed in #1581.

[iker-barriocanal]

Adding an Unreleased empty entry back to the changelog is addressed in #1582.