Bump testcontainers.version from 1.20.6 to 1.21.0 (#4435)

Bumps `testcontainers.version` from 1.20.6 to 1.21.0.

Updates `org.testcontainers:mockserver` from 1.20.6 to 1.21.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](https://github.com/testcontainers/testcontainers-java/compare/1.20.6...1.21.0)

Updates `org.testcontainers:junit-jupiter` from 1.20.6 to 1.21.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](https://github.com/testcontainers/testcontainers-java/compare/1.20.6...1.21.0)

---
updated-dependencies:
- dependency-name: org.testcontainers:mockserver
  dependency-version: 1.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:junit-jupiter
  dependency-version: 1.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pom.xml

@@ -23,7 +23,7 @@
 		<bintray.package>netflix</bintray.package>
 		<spring-cloud-commons.version>4.3.0-SNAPSHOT</spring-cloud-commons.version>
 		<spring-cloud-config.version>4.3.0-SNAPSHOT</spring-cloud-config.version>
-		<testcontainers.version>1.20.6</testcontainers.version>
+		<testcontainers.version>1.21.0</testcontainers.version>
 		<mockserverclient.version>5.15.0</mockserverclient.version>
 
 		<!-- Sonar -->