Readme: Dependency typo error

```
kapt "com.github.Sserra90.bulldog:bulldog-processor:$bulldog"
 implementation "com.github.Sserra90.bulldog:bulldog-runtime:$bulldog"
```
should be changed to
```
kapt "com.github.Sserra90.Bulldog:bulldog-processor:$bulldog"
 implementation "com.github.Sserra90.Bulldog:bulldog-runtime:$bulldog"
```
based on your jitpack https://jitpack.io/#Sserra90/Bulldog/v0.2-beta