Update log4j to version 2.14.1

Beam uses a version of log4j that is reported by some security tools to have some security issues. Notice that Beam's use of log4j should not be impacted by the issue.
See https://nvd.nist.gov/vuln/detail/CVE-2017-5645

The update in the vendored grpc module is to ensure it gets updated too in a future release of our vendored dependencies. Notice that this is a runtime dep for users so they are free to provide their own version so less of an issue.