Barman 3.10.0 Released

[EDB](https://www.enterprisedb.com) is pleased to announce the release of Barman 3.10.0.

## Highlights of this release:
### Features:
* Limit the average bandwidth used by `barman-cloud-backup` when backing
up to either AWS S3 or Azure Blob Storage according to the value set by
a new CLI option `--max-bandwidth`.
* Add the new configuration option `lock_directory_cleanup`
That enables cron to automatically clean up the barman_lock_directory
from unused lock files.
* Add support for a new type of configuration called `model`.
The model acts as a set of overrides for configuration options
for a given Barman server.
* Add a new barman command `barman config-update` that allows the creation
and the update of configurations using JSON
* Related to this Barman release, [pg_backup_api](https://github.com/EnterpriseDB/barman/blob/master/NEWS) has been updated and released to support these new features. As a result, Barman now supports changes in the configuration whilst it's running. This pg-backup-api release adds the required endpoints to trigger that switch when requested.

### Bug fixes:
* Fix a bug that caused `--min-chunk-size` to be ignored when using `barman-cloud-backup` as a hook script in Barman.

This information is also published in the [NEWS](https://github.com/EnterpriseDB/barman/blob/master/NEWS) for Barman.

### About Barman
Backup and Recovery Manager (or Barman) is an open-source administration tool for remote backups and disaster recovery of PostgreSQL servers in business-critical environments. It relies on PostgreSQL’s robust and reliable Point-In-Time Recovery technology, allowing DBAs to remotely manage a complete catalog of backups and the recovery phase of multiple remote servers – all from one location. Barman is distributed under GNU GPL 3 and maintained by [EDB](https://www.enterprisedb.com).