scikitplot: incorrect extra requirement

```
user@host:~> mkdir temp
user@host:~> cd temp
user@host:~/temp> echo import scikitplot > bug.py
user@host:~/temp> pipreqs
INFO: Successfully saved requirements file in /home/bers/temp/requirements.txt
user@host:~/temp> more requirements.txt
scikit_plot==0.3.7
scikitplot==0.1.1
```

The last line should not be there.

Reproduce the issue using the commands and import shown in the report, then trace pipreqs' dependency-name resolution and requirements generation. Done means the generated requirements.txt no longer includes the extra scikitplot entry; no source file or test is named, so locating the relevant code and adding coverage will require repository investigation.

Written by the indexing model from the issue text.