Fix deadlock in REST API for 0.9.0 (#257)

Updates to 0.9.0 version to resolve deadlock issue in REST API for
asynchronous VCF annotation.
- Remove unnecessary re-creation of `AsyncResult` in `get_result()`
- Upgrade Celery to 5.5
- Improve observability with additional logging
- Fix calculation for retry-after header

build: pin VRS-Python 2.0a12 (#114)

See #111

* fixed version reporting in info route

* pip install anyvar within container

serve anyvar on port 80 to ease GCP deployment