build(deps): bump org.testcontainers:mongodb from 1.19.3 to 1.21.3

Bumps [org.testcontainers:mongodb](https://github.com/testcontainers/testcontainers-java) from 1.19.3 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@1.19.3...1.21.3)

---
updated-dependencies:
- dependency-name: org.testcontainers:mongodb
  dependency-version: 1.21.3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

build.gradle

@@ -97,9 +97,9 @@ dependencies {
     testImplementation "org.hamcrest:hamcrest-library"
 
     // testcontainers
-    testImplementation "org.testcontainers:testcontainers:1.19.3"
-    testImplementation "org.testcontainers:mongodb:1.19.3"
-    testImplementation "org.testcontainers:junit-jupiter:1.19.3"
+    testImplementation "org.testcontainers:testcontainers:1.21.3"
+    testImplementation "org.testcontainers:mongodb:1.21.3"
+    testImplementation "org.testcontainers:junit-jupiter:1.21.3"
 }
 
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