build(deps): bump testcontainers from 1.20.2 to 1.20.3

Bumps `testcontainers` from 1.20.2 to 1.20.3.

Updates `org.testcontainers:gcloud` from 1.20.2 to 1.20.3
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.20.2...1.20.3)

Updates `org.testcontainers:junit-jupiter` from 1.20.2 to 1.20.3
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.20.2...1.20.3)

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

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

gradle/libs.versions.toml

@@ -11,7 +11,7 @@ googleCloudBom = "26.49.0"
 identityhub = "0.3.1"
 junit = "5.11.2"
 restAssured = "5.5.0"
-testcontainers = "1.20.2"
+testcontainers = "1.20.3"
 
 [libraries]
 edc-api-management = { module = "org.eclipse.edc:management-api", version.ref = "edc" }