Bump waitress from 1.4.3 to 2.1.1

Bumps [waitress](https://github.com/Pylons/waitress) from 1.4.3 to 2.1.1.
- [Release notes](https://github.com/Pylons/waitress/releases)
- [Changelog](https://github.com/Pylons/waitress/blob/master/CHANGES.txt)
- [Commits](Pylons/waitress@v1.4.3...v2.1.1)

---
updated-dependencies:
- dependency-name: waitress
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -5,7 +5,7 @@ itsdangerous==1.1.0
 Jinja2==2.11.2
 MarkupSafe==1.1.1
 PyMySQL==0.9.3
-waitress==1.4.3
+waitress==2.1.1
 Werkzeug==1.0.1
 google-auth==1.15.0
 requests==2.23.0