Pin gnocchi versions in stable releases

[Yadnesh Kulkarni]

Currently all stable releases of openstack build Gnocchi by cloning master branch due to which a lot of compatibility issues among python modules are surfacing while install Gnocchi from source. Also, in the near future it will start using sqlalchemy2, however the older/stable releases of OSP will continue to use sqlalchemy1.4.

If we do not pair correct releases of Gnocchi & OpenStack more issues like [1] will surface.

[1] https://990f69bf787446dd40f3-82c7c26c1c9d82596e9efade16533251.ssl.cf5.rackcdn.com/892743/1/check/telemetry-dsvm-integration/8aef4e8/controller/logs/screen-gnocchi-api.txt

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ceilometer yoga-eom release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ceilometer wallaby-eom release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ceilometer xena-eom release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ceilometer zed-eom release.