Update pymongo requirement from ~=4.7.2 to ~=4.7.3

Updates the requirements on [pymongo](https://github.com/mongodb/mongo-python-driver) to permit the latest version.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/master/doc/changelog.rst)
- [Commits](https://github.com/mongodb/mongo-python-driver/compare/4.7.2...4.7.3)

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

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

requirements.txt

@@ -2,7 +2,7 @@ flask~=3.0.3
 PyYaml==6.0.1
 graypy~=2.1.0
 requests~=2.32.3
-pymongo~=4.7.2
+pymongo~=4.7.3
 waitress~=3.0.0
 colorlog~=6.8.2
 bleach~=6.1.0