Bump org.testcontainers:testcontainers-bom from 1.20.6 to 1.21.0 (#322)

Bumps [org.testcontainers:testcontainers-bom](https://github.com/testcontainers/testcontainers-java) 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](testcontainers/testcontainers-java@1.20.6...1.21.0)

---
updated-dependencies:
- dependency-name: org.testcontainers:testcontainers-bom
  dependency-version: 1.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

internal-bom/build.gradle.kts

@@ -11,7 +11,7 @@ javaPlatform {
 
 dependencies {
     api(platform("org.junit:junit-bom:5.12.2"))
-    api(platform("org.testcontainers:testcontainers-bom:1.20.6"))
+    api(platform("org.testcontainers:testcontainers-bom:1.21.0"))
     api(platform("io.github.mfvanek:pg-index-health-bom:0.14.6"))
     api(platform("org.mockito:mockito-bom:5.17.0"))
     api(platform("org.assertj:assertj-bom:3.27.3"))