Bump version to 0.12.3 (tensorflow#527)

* Bump version to 0.12.3

* Depend on tfjs-layers 0.7.1
* Depend on tfjs-converter 0.5.2

Update union to 0.12.2 with core update to 0.12.4. (tensorflow#509)

Release new patch version 0.12.1 (tensorflow#507)

Bump version to 0.12.0 (tensorflow#487)

* Bump version to 0.12.0

Bump version to 0.11.7 (tensorflow#456)

* Bump version to 0.11.7

Dependency versions:
tfjs-core: 0.11.6 --> 0.11.9
tfjs-layer: 0.6.6 --> 0.6.7
tfjs-converter: 0.4.1 --> 0.4.3

Bump version to 0.11.6 (tensorflow#405)

tfjs-core: 0.11.5 --> 0.11.6
tfjs-layers: 0.6.5 --> 0.6.6

Bump version to 0.11.5 (tensorflow#399)

tfjs-core: 0.11.4 --> 0.11.5
tfjs-layers: 0.6.4 --> 0.6.5

increase the version to 0.11.3 (tensorflow#371)

* increate the version to 0.11.3

* bump core version to 0.11.4

* update layer to 0.6.4

Increase dependency versions (tensorflow#334)

- tfjs-core: 0.11.0 --> 0.11.1
- tfjs-layers: 0.6.1 --> 0.6.2

It should be okay to do this without increasing the version of union
because no npm has been published yet and no git release has been
tagged yet.

Bump version to 0.11.1 (tensorflow#309)