Enabling observability behind proxy will make mysql units fail

[Guillaume Boutry]

Enabling the logging relation between mysql charm (rev 127) and loki will require the charm to download an artifact from github. The loki_push_api (version 18) does not support proxies, and will fail to use the proxy to download the artifact. This will fail the mysql units.

Newer versions of this library support reading from proxy settings from JUJU_* vars

Linked issue: https://github.com/canonical/mysql-k8s-operator/issues/408

[Hemanth Nakkina (hemanth-n)]

Newer versions of the library support reading proxy information from JUJU_... vars: https://github.com/canonical/loki-k8s-operator/blob/9f7580e9b441697246f566c63dd7bd93858c2a33/lib/charms/loki_k8s/v0/loki_push_api.py#L2123

sunbeam-charms now uses library that contains the fix
https://opendev.org/openstack/sunbeam-charms/commit/bd1d5b0350c03b0a595ae331d172bd9edfe84124

This needs verification

[Guillaume Boutry (gboutry)]

mysql-k8s 153 (current stable), has the fixed library