Bump org.testcontainers:testcontainers-bom (#9679)

Bumps the development-dependencies group with 1 update: [org.testcontainers:testcontainers-bom](https://github.com/testcontainers/testcontainers-java).


Updates `org.testcontainers:testcontainers-bom` 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](https://github.com/testcontainers/testcontainers-java/compare/1.20.3...1.20.4)

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

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

build.gradle

@@ -116,7 +116,7 @@ ext {
     springSecurityVersion = '6.4.0'
     springVersion = '6.2.0'
     springWsVersion = '4.0.11'
-    testcontainersVersion = '1.20.3'
+    testcontainersVersion = '1.20.4'
     tomcatVersion = '10.1.33'
     xmlUnitVersion = '2.10.0'
     xstreamVersion = '1.4.21'