Bump com.google.errorprone:error_prone_core from 2.20.0 to 2.21.1

Bumps [com.google.errorprone:error_prone_core](https://github.com/google/error-prone) from 2.20.0 to 2.21.1.
- [Release notes](https://github.com/google/error-prone/releases)
- [Commits](google/error-prone@v2.20.0...v2.21.1)

---
updated-dependencies:
- dependency-name: com.google.errorprone:error_prone_core
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -98,7 +98,7 @@
     <auto-common.version>1.2.2</auto-common.version>
     <java.version>1.8</java.version>
     <guava.version>32.1.2-jre</guava.version>
-    <errorprone.version>2.20.0</errorprone.version>
+    <errorprone.version>2.21.1</errorprone.version>
   </properties>
 
   <dependencyManagement>