[MavenCapsule] Dependencies with wildcard versions fail

If I have a dependency in my build.gradle file:

```kotlin
dependencies {
  compile("com.example:library:+")
}
```

I would expect it to be resolved to the most recent version at the time of the build:

```
// MANIFEST.MF
Dependencies: com.example:library:1.2.3
```

It is currently saved as `com.example:library:+`, which Capsule cannot understand.