Build(deps): Bump waitress in /examples/falcon_mongoengine (#240)

Bumps [waitress](https://github.com/Pylons/waitress) from 2.1.2 to 3.0.1.
- [Release notes](https://github.com/Pylons/waitress/releases)
- [Changelog](https://github.com/Pylons/waitress/blob/main/CHANGES.txt)
- [Commits](Pylons/waitress@v2.1.2...v3.0.1)

---
updated-dependencies:
- dependency-name: waitress
  dependency-version: 3.0.1
  dependency-type: direct:production
...

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Author: dependabot[bot]

examples/falcon_mongoengine/requirements.txt

@@ -1,6 +1,6 @@
 falcon==2.0.0
 mongoengine==0.17.0
 graphene-mongo
-waitress==2.1.2
+waitress==3.0.1
 pytest==4.6.3
 mongomock==3.16.0