* 6a24f2d7b == override parameters are non-nullable (flutter/plugins#6900)

* b9206bcfe [espresso]: Bump espresso-accessibility and espresso-idling-resource from 3.1.0 to 3.5.1 in /packages/espresso/android (flutter/plugins#6933)

* b1797c2bb [file_selector] Switch to Pigeon for macOS (flutter/plugins#6902)

* 620a059d6 [google_sign_in] Renames generated folder to js_interop. (flutter/plugins#6915)