1.8.3

This release fixes the CI pipeline to run on external pull requests and
makes tests compatible with any tarantool 3.x version.

Changed

• CI is run on pull requests in addition to branch pushes; the runs are
  skipped for pull requests from the base repository to avoid duplicates
  (#555).

Fixed

• config_metrics_test: disable system alerts only if the config.checks
  option exists (instead of a tarantool version based check), so the test
  passes on any tarantool 3.x version (#553).