This is a patched release of 3.4.5 for continued python 2 support.
This release cherry-picks cve patches:
- Resolve serious ReDoS in PunktSentenceTokenizer (nltk#2869) - CVE-2021-43854
- Resolve ReDoS opportunity by fixing incorrectly specified regex (nltk#2906) - CVE-2021-3842
- Resolved ReDoS vulnerability in Corpus Reader (nltk#2816) - CVE-2021-3828