chore: bump next version to v0.15.0 (#9073)

* tests: avoid use of removed unscoped enums

Signed-off-by: Justin Chadwell <[email protected]>

* chore: bump next version to v0.15.0

Signed-off-by: Justin Chadwell <[email protected]>

* ci: run daggerverse-preview on changelogs

`.changes/.next` isn't a good identifier for whether we're actually
doing a release - a better indicator is whether we have a new changelog.

Signed-off-by: Justin Chadwell <[email protected]>

* tests: remove future tests for v0.15.0

Signed-off-by: Justin Chadwell <[email protected]>

* ci: allow specifying engine lint targets

Signed-off-by: Justin Chadwell <[email protected]>

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Signed-off-by: Justin Chadwell <[email protected]>