Update req.txt

Adding the `wordcounter` package for the error:
```shell
Traceback (most recent call last):
File "/home/user/app/app.py", line 24, in <module>
from wordcloud import WordCloud
ModuleNotFoundError: No module named 'wordcloud'
```

requirements.txt

@@ -7,3 +7,4 @@ matplotlib-inline==0.1.6
 matplotlib-venn==0.11.9
 seaborn==0.12.2
 plotly==5.15.0
+wordcloud==1.9.2