feat!: configure_snmp_agent with the caller's values replaces fix_snmp (0.3.0)

fix_snmp wrote an application's snmpd.conf (community public, Managed
by netOrk, netork@localhost) and judged itself by a local snmpget.

The drivers implement napalm-device-types 4.13's SnmpAgentMixin steps
instead: net-snmp installed, snmpd.conf with one rocommunity line per
allowed source (staged without privilege, installed by root), snmpd
enabled and restarted. pf and ipfw rules stay the operator's. A
community or text that would break the file is refused. The caller
verifies with its own SNMP client.

Also get_management_peer() from SSH_CONNECTION, ensure_package from
the base package, and get_snmp_config no longer assumes "public".

BREAKING CHANGE: run_device_action is removed. Requires
napalm-device-types 4.13.

Part of #12 (the OpenBSD new_version text is still open).

CHANGELOG.md

@@ -7,6 +7,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.3.0] - 2026-10-17
+
+### Changed
+- **Breaking:** `run_device_action("fix_snmp")` is gone. The drivers implement
+  napalm-device-types 4.13's `configure_snmp_agent(settings)` template instead, and
+  the caller supplies every value: one `rocommunity` line per allowed source, contact
+  and location as given. No community, contact or location of an application is built
+  in any more. pf and ipfw rules are left to the operator. Requires
+  napalm-device-types 4.13.0 or later.
+- `get_snmp_config` no longer assumes the community `public` when the file names none.
+
+### Added
+- `get_management_peer()`: the address the host sees the SSH connection come from.
+- `ensure_package(name)` from the base package.
+
 ## [0.2.1] - 2026-10-16
 
 ### Fixed