Bump testcontainersVersion from 1.15.3 to 1.16.0

Bumps `testcontainersVersion` from 1.15.3 to 1.16.0.

Updates `testcontainers` from 1.15.3 to 1.16.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/master/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.15.3...1.16.0)

Updates `spock` from 1.15.3 to 1.16.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/master/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.15.3...1.16.0)

Updates `influxdb` from 1.15.3 to 1.16.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/master/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.15.3...1.16.0)

Updates `postgresql` from 1.15.3 to 1.16.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/master/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.15.3...1.16.0)

Updates `couchbase` from 1.15.3 to 1.16.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/master/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.15.3...1.16.0)

---
updated-dependencies:
- dependency-name: org.testcontainers:testcontainers
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:spock
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:influxdb
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:postgresql
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:couchbase
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -18,7 +18,7 @@ ext {
 	//version (changing these should be considered thoroughly!)
 	javaVersion = JavaVersion.VERSION_1_8
 	tscfgVersion = '0.9.9'
-	testcontainersVersion = '1.15.3'
+	testcontainersVersion = '1.16.0'
 
 	scriptsLocation = 'gradle' + File.separator + 'scripts' + File.separator //location of script plugins
 }