feat: switch off the fix templates QTS cannot take (0.4.0)

napalm-linux 0.8 implements napalm-device-types' fix templates. QTS has
no apt, dnf or opkg and sets its SNMP agent in its own UI, so
configure_snmp_agent, configure_package_proxy and ensure_package are
None here: a capability check answers no instead of offering a fix
that fails, as the inherited fix_snmp and fix_apt_proxy did.

get_device_warnings returns nothing: the inherited one asked for
updates, which is None here, and logged a TypeError on every poll.

The role test follows napalm-linux's get_os_users.

Closes #6. Part of #7.

CHANGELOG.md

@@ -7,6 +7,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.4.0] – 2026-10-17
+
+### Changed
+- Requires napalm-linux 0.8.0, whose fixes are napalm-device-types' templates.
+  `configure_snmp_agent`, `configure_package_proxy` and `ensure_package` are switched
+  off (`None`): QTS has no apt, dnf or opkg, and its SNMP agent is set in its own UI.
+  Before, the inherited SNMP and apt-proxy fixes were offered and failed.
+
+### Fixed
+- `get_device_warnings` no longer logs a TypeError on every poll: the inherited one
+  asked for updates, which QTS cannot list (#6).
+
 ## [0.3.0] – 2026-10-08
 
 ### Removed