Removed unnecessary file separator from classpath stub provider

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/ClasspathStubProvider.java

@@ -132,11 +132,11 @@ public class ClasspathStubProvider implements StubDownloaderBuilder {
 				if (groupAndArtifactMatcher.matches()) {
 					MatchResult groupAndArtifactResult = groupAndArtifactMatcher
 							.toMatchResult();
-					return groupAndArtifactResult.group(2) + File.separator
+					return groupAndArtifactResult.group(2)
 							+ groupAndArtifactResult.group(3);
 				}
 				else {
-					throw new IllegalArgumentException("Illegal uri [${uri}]");
+					throw new IllegalArgumentException("Illegal uri [" + uri + "]");
 				}
 			}
 		};