[url_launcher_web] Fix link in README (flutter#2932)

Co-authored-by: Markus Aksli <68219924+markusaksli-nc@users.noreply.github.com>

Fix unguarded availability in Camera plugin (flutter#2928)

* Fix unguarded availability in Camera plugin

[device_info] Moved device_info to a subdir (flutter#2923)

(This is preparation for the federation of the plugin)

[google_maps_flutter] Call platform.dispose from widget. (flutter#2909)

[google_maps_flutter] Pin GoogleMaps cocoapod dep to last good known …

…version (flutter#2924)

[device_info] Moved device_info to a subdir (flutter#2923)

(This is preparation for the federation of the plugin)

[e2e] Revert performance tracker utilities (flutter#2917)

(To be moved to flutter_test)

[camera] Improving handling when camera permissions are not granted. (f…

…lutter#2848)

[google_maps_flutter_platform_interface] Add dispose method. (flutter…

…#2908)

This method gives the plugin writers a chance to release the resources that they've acquired throughout the operation of the plugin (think of it as an "inverse" of the "init" method).

[google_maps_flutter + platform] Tweaks to enable a web implementatio…

…n. (flutter#2903)

This change tweaks slightly the core maps plugin and the platform interface package to make the web implementation possible.

The most important changes are two:

* The core plugin now passes a constant identifier to the buildView platform call, so the web version can cache effectively the contents of the platform view, so it doesn't repaint. This might go away once Scenelets for web come online.
* The platform interface now encodes the (optional) width and height of custom Icons for Markers, so the web can render High DPI assets at the correct size.

The rest are some examples to the 'example' app so it can be run on web.