Switch thin repo to maven.

Signed-off-by: Olga Maciaszek-Sharma <olga.maciaszek-sharma@broadcom.com>

Author: OlgaMaciaszek

docker/spring-cloud-contract-stub-runner-docker/Dockerfile

@@ -1,7 +1,7 @@
 FROM ubuntu:20.04
 
 ARG SDKMAN_JAVA_INSTALLATION=17.0.1-tem
-ARG THIN_REPO=https://repo.spring.io/snapshot
+ARG THIN_REPO=https://repo1.maven.org/maven2/
 
 LABEL Author="Marcin Grzejszczak <mgrzejszczak@pivotal.io>"
 LABEL Author="Bastian Doetsch <bdoetsch@vmware.com>"