build(deps): bump testcontainersVersion from 1.21.0 to 1.21.3

Bumps `testcontainersVersion` from 1.21.0 to 1.21.3.

Updates `org.testcontainers:junit-jupiter` from 1.21.0 to 1.21.3
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.21.0...1.21.3)

Updates `org.testcontainers:kafka` from 1.21.0 to 1.21.3
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.21.0...1.21.3)

---
updated-dependencies:
- dependency-name: org.testcontainers:junit-jupiter
  dependency-version: 1.21.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.testcontainers:kafka
  dependency-version: 1.21.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

build.gradle

@@ -47,7 +47,7 @@ ext {
     junit5Version = "5.12.2"
     kafkaVersion = "2.0.1"
     log4jVersion = "2.24.3"
-    testcontainersVersion = "1.21.0"
+    testcontainersVersion = "1.21.3"
 }
 
 distributions {