deps: bump org.testcontainers:testcontainers-bom from 1.20.3 to 1.20.4 (#3427)

Bumps [org.testcontainers:testcontainers-bom](https://github.com/testcontainers/testcontainers-java) from 1.20.3 to 1.20.4.
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.20.3...1.20.4)

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

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

Author: dependabot[bot]

spring-cloud-gcp-samples/pom.xml

@@ -24,7 +24,7 @@
 		<!-- Dependency versions -->
 		<spring-native.version>0.12.2</spring-native.version>
 		<google-cloud-graalvm-support.version>0.7.0</google-cloud-graalvm-support.version>
-		<testcontainers.version>1.20.3</testcontainers.version>
+		<testcontainers.version>1.20.4</testcontainers.version>
 
 		<!-- Checkstyle versions. Keep in sync with ../pom.xml -->
 		<maven-checkstyle-plugin.version>3.6.0</maven-checkstyle-plugin.version>