Bump graphql-java-extended-scalars in /plugins/maven/example-client to 20.0 (#1089)

Bumps [graphql-java-extended-scalars](https://github.com/graphql-java/graphql-java-extended-scalars) from 16.0.1 to 20.0.
- [Release notes](https://github.com/graphql-java/graphql-java-extended-scalars/releases)
- [Commits](https://github.com/graphql-java/graphql-java-extended-scalars/commits/20.0)

---
updated-dependencies:
- dependency-name: com.graphql-java:graphql-java-extended-scalars
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Bogdan Kobylynskyi <[email protected]>

Author: dependabot[bot]

plugins/maven/example-client/pom.xml

@@ -144,7 +144,7 @@
         <dependency>
             <groupId>com.graphql-java</groupId>
             <artifactId>graphql-java-extended-scalars</artifactId>
-            <version>16.0.1</version>
+            <version>20.0</version>
         </dependency>