Bump thymeleaf from 3.0.9.RELEASE to 3.0.11.RELEASE

Bumps [thymeleaf](https://github.com/thymeleaf/thymeleaf) from 3.0.9.RELEASE to 3.0.11.RELEASE.
- [Release notes](https://github.com/thymeleaf/thymeleaf/releases)
- [Changelog](https://github.com/thymeleaf/thymeleaf/blob/3.0-master/ChangeLog.txt)
- [Commits](thymeleaf/thymeleaf@thymeleaf-3.0.9.RELEASE...thymeleaf-3.0.11.RELEASE)

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

Author: dependabot-support

external-dependencies.gradle

@@ -51,7 +51,7 @@ ext {
 
     markdown = 'org.markdownj:markdownj-core:0.4'
 
-    thymeleaf = 'org.thymeleaf:thymeleaf:3.0.9.RELEASE'
+    thymeleaf = 'org.thymeleaf:thymeleaf:3.0.11.RELEASE'
 
     dropwizardLogstash = "uk.gov.ida:dropwizard-logstash:1.1.2-build_46"