Release 1.3.1 (#53)

## What

Folds the pending changesets into the 1.3.1 release. Version propagated
by `scripts/create_version.dart`, all version checks pass, `.changes/`
emptied.

## Changelog

* Changed: Remove the direct flutter_webrtc dependency, screen share now
uses livekit_client helpers (#52)
* Docs: Add AudioVisualizerWidget documentation (#48)

## Why now

Published 1.3.0 pins flutter_webrtc 1.2.1 exactly, which forces
resolution down to livekit_client 2.6.1 for every consumer including the
agent starter (#49). This release depends on livekit_client ^2.10.0 with
no flutter_webrtc pin, so resolution always follows whatever
livekit_client pins.

## After merge

Tag `v1.3.1` to publish. With the pin gone there is no expected
validation warning, so the stock publish workflow should pass as is.

Downstream: agent-starter-flutter bumps to `livekit_components: ^1.3.1`
and `livekit_client: ^2.10.0`.

v1.3.0 (#46)

v1.2.3 (#42)

1.2.2+hotfix.1 (#37)

v1.2.2 (#35)

release: 1.2.1 (#23)

* release: 1.2.0.

* fix layout for media select button.

* expose more fields for TrackIdentifier.

* more changes.

* more changes.

* update.

* fix.

* update.

* update.

* dart run import_sorter:main --no-comments.

* update.

* fix.

* release: 1.2.1.

* release: 1.2.1.

release: 1.2.0. (#21)

Update publish.yaml (#18)

release: 1.1.0.

release: 1.0.1. (#5)