Bump confluent.version from 7.9.2 to 8.1.1

Bumps `confluent.version` from 7.9.2 to 8.1.1.

Updates `io.confluent:kafka-schema-registry-client` from 7.9.2 to 8.1.1
- [Commits](confluentinc/schema-registry@v7.9.2...v8.1.1)

Updates `io.confluent:kafka-avro-serializer` from 7.9.2 to 8.1.1
- [Commits](confluentinc/schema-registry@v7.9.2...v8.1.1)

Updates `io.confluent:kafka-connect-avro-converter` from 7.9.2 to 8.1.1
- [Commits](confluentinc/schema-registry@v7.9.2...v8.1.1)

Updates `io.confluent:kafka-schema-registry-client-encryption` from 7.9.2 to 8.1.1
- [Commits](confluentinc/schema-registry@v7.9.2...v8.1.1)

---
updated-dependencies:
- dependency-name: io.confluent:kafka-schema-registry-client
  dependency-version: 8.1.1
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: io.confluent:kafka-avro-serializer
  dependency-version: 8.1.1
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: io.confluent:kafka-connect-avro-converter
  dependency-version: 8.1.1
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: io.confluent:kafka-schema-registry-client-encryption
  dependency-version: 8.1.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

pom.xml

@@ -56,7 +56,7 @@
         <kafka.version>3.9.1</kafka.version>
         <awaitility.version>4.2.2</awaitility.version>
         <assertj-core.version>3.26.3</assertj-core.version>
-        <confluent.version>7.9.2</confluent.version>
+        <confluent.version>8.1.1</confluent.version>
         <!--Compatible protobuf version https://github.com/confluentinc/common/blob/v7.7.0/pom.xml#L91 -->
         <protobuf.version>3.25.5</protobuf.version>
         <guava.version>33.4.0-jre</guava.version>