Branch name can't be resolved (plugin versions 2.0.3 and 2.0.4)

Steps to reproduce
* create settings.gradle
```
plugins { id 'com.alexvasilkov.git-dependencies' version '2.0.3' } // 2.0.4 also does not work

git {
fetch 'https://github.com/alexvasilkov/GradleGitDependenciesPlugin.git' , {
dir "$rootDir/testing"
commit 'master'
}
}

rootProject.name = 'testing'
```
* run ./gradlew

result
```
$ ./gradlew
Git dependency: Added 'GradleGitDependenciesPlugin'
Git dependency: Clone started 'https://github.com/alexvasilkov/GradleGitDependenciesPlugin.git' at version 'master'

FAILURE: Build failed with an exception.

* Where:
Settings file '/home/XXX/testing/settings.gradle' line: 4

* What went wrong:
A problem occurred evaluating settings 'testing'.
> Ref master cannot be resolved
```