Bump testContainersVersion from 1.19.8 to 1.20.0 in /Plan

Bumps `testContainersVersion` from 1.19.8 to 1.20.0.

Updates `org.testcontainers:testcontainers` from 1.19.8 to 1.20.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.19.8...1.20.0)

Updates `org.testcontainers:junit-jupiter` from 1.19.8 to 1.20.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.19.8...1.20.0)

Updates `org.testcontainers:nginx` from 1.19.8 to 1.20.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.19.8...1.20.0)

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

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

Plan/build.gradle

@@ -108,7 +108,7 @@ subprojects {
         junitVersion = "5.10.3"
         mockitoVersion = "5.12.0"
         seleniumVersion = "4.22.0"
-        testContainersVersion = "1.19.8"
+        testContainersVersion = "1.20.0"
         swaggerVersion = "2.2.22"
     }