Bump protobuf-java from 2.5.0 to 3.16.3

Bumps [protobuf-java](https://github.com/protocolbuffers/protobuf) from 2.5.0 to 3.16.3.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](protocolbuffers/protobuf@v2.5.0...v3.16.3)

---
updated-dependencies:
- dependency-name: com.google.protobuf:protobuf-java
  dependency-type: direct:production
...

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

connect/pom.xml

@@ -32,7 +32,7 @@
   <url>https://spark.apache.org/</url>
   <properties>
     <sbt.project.name>connect</sbt.project.name>
-    <protobuf.version>3.21.1</protobuf.version>
+    <protobuf.version>3.16.3</protobuf.version>
     <guava.version>31.0.1-jre</guava.version>
     <io.grpc.version>1.47.0</io.grpc.version>
     <tomcat.annotations.api.version>6.0.53</tomcat.annotations.api.version>

connector/kinesis-asl-assembly/pom.xml

@@ -62,11 +62,11 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
-      <version>2.6.1</version>
+      <version>3.16.3</version>
       <!-- 
          We are being explicit about version here and overriding the 
          spark default of 2.5.0 because KCL appears to have introduced 
-         a dependency on protobuf 2.6.1 somewhere between KCL 1.4.0 and 1.6.1.
+         a dependency on protobuf 3.16.3 somewhere between KCL 1.4.0 and 1.6.1.
        -->
     </dependency>
     <dependency>

pom.xml

@@ -117,7 +117,7 @@
     <log4j.version>2.19.0</log4j.version>
     <!-- make sure to update IsolatedClientLoader whenever this version is changed -->
     <hadoop.version>3.3.4</hadoop.version>
-    <protobuf.version>2.5.0</protobuf.version>
+    <protobuf.version>3.16.3</protobuf.version>
     <yarn.version>${hadoop.version}</yarn.version>
     <zookeeper.version>3.6.2</zookeeper.version>
     <curator.version>2.13.0</curator.version>