Bump pymongo from 3.7.2 to 4.6.3 in /scripts/migrates-aws-s3

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 3.7.2 to 4.6.3.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/master/doc/changelog.rst)
- [Commits](mongodb/mongo-python-driver@3.7.2...4.6.3)

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

Signed-off-by: dependabot[bot] <[email protected]>

scripts/migrates-aws-s3/requirements.txt

@@ -1,3 +1,3 @@
-pymongo==3.7.2
+pymongo==4.6.3
 boto3==1.9.188
 s3transfer==0.2.1