Bump versions for the 1.1.0-beta1 release (google#447)

Bump the version. (google#429)

flexbox-layout has been considered as stable for a while, but from this
on, it starts to follow the semantic versioning.

Bump up the library version

Bump up the version to 0.3.1

Bump the version to 0.3.0. (google#324)

For a stable release including RecyclerView integration:
- Bump the library version.
- Update the README

Bump up the alpha version to 0.3.0-alpha4 (google#310)

Update the Firebase Test Lab command. (google#305)

Broaden OS levels to test.

Bump up the alpha version to 0.3.0-alpha3 (google#241)

Bump the stable version to 0.2.6 (google#232)

Bump up alpha version (google#194)