Replication actions will fail when pg 11 is released

[Tim McNamara]

Within actions/actions.py, there are a few version checks that will break when the upstream major version number increments past 10, e.g.:

  def replication_pause(params):
      ...
      if postgresql.has_version("10"):
          cur.execute("SELECT pg_is_wal_replay_paused()")

https://github.com/stub42/postgresql-charm/blob/cc4527c35ad7452e90cd73c697e5abd33d23c73c/actions/actions.py#L43

[Stuart Bishop (stub)]

has_version() returns true if the version is *at least* as high as the parameter.

(I do expect there will be other issues though, starting with lib/pg_settings_{11,12}.json doesn't exist yet)