update sonatype grpc-core dependency/exclusion and add comment
<artifactId>guava</artifactId>
<version>31.1-jre</version>
</exclude>
+ <!-- sonatype https://ossindex.sonatype.org/vulnerability/sonatype-2021-0818
+ false positive? related bug https://github.com/grpc/grpc-java/issues/8311
+ has been fixed -->
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-core</artifactId>
- <version>1.50.2</version>
+ <version>1.51.0</version>
</dependency>
<exclude>
<!-- CVE-2018-18928 does affect the java library not just the c/c++ library,
