deps: update dependency com.google.protobuf:protobuf-java-util to v3.21.0 (#1375)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.protobuf:protobuf-java-util](https://developers.google.com/protocol-buffers/) ([source](https://togithub.com/protocolbuffers/protobuf)) | `3.20.1` -> `3.21.0` | [![age](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protobuf-java-util/3.21.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protobuf-java-util/3.21.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protobuf-java-util/3.21.0/compatibility-slim/3.20.1)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protobuf-java-util/3.21.0/confidence-slim/3.20.1)](https://docs.renovatebot.com/merge-confidence/) |

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Author: renovate-bot

README.md

@@ -56,13 +56,13 @@ implementation 'com.google.cloud:google-cloud-bigquerydatatransfer'
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-bigquerydatatransfer:2.2.0'
+implementation 'com.google.cloud:google-cloud-bigquerydatatransfer:2.2.1'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-bigquerydatatransfer" % "2.2.0"
+libraryDependencies += "com.google.cloud" % "google-cloud-bigquerydatatransfer" % "2.2.1"
 ```
 
 ## Authentication

samples/install-without-bom/pom.xml

@@ -35,7 +35,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java-util</artifactId>
-      <version>3.20.1</version>
+      <version>3.21.0</version>
     </dependency>
 
     <dependency>

samples/snapshot/pom.xml

@@ -35,7 +35,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java-util</artifactId>
-      <version>3.20.1</version>
+      <version>3.21.0</version>
     </dependency>
 
     <dependency>