Bump waitress from 1.1.0 to 1.4.0 (#137)

Bumps [waitress](https://github.com/Pylons/waitress) from 1.1.0 to 1.4.0.
- [Release notes](https://github.com/Pylons/waitress/releases)
- [Changelog](https://github.com/Pylons/waitress/blob/master/CHANGES.txt)
- [Commits](Pylons/waitress@v1.1.0...v1.4.0)

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -13,7 +13,7 @@ tweepy==3.7.0
 metadata_parser==0.9.20
 hug==2.4.0
 hug-middleware-cors==1.0.0
-waitress==1.1.0
+waitress==1.4.0
 SpeechRecognition
 pyjwt==1.6.4
 SQLAlchemy>=1.3.0