Use String.replace in MetadataEncoder

Use String.replace instead of replaceAll in MetadataEncoder; since Java 9, String.replace
no longer uses a regex, while replaceAll does. The use case here of replacing a single
character does not require a regex.

Closes gh-35025

Signed-off-by: Patrick Strawderman <[email protected]>

Author: kilink

spring-messaging/src/main/java/org/springframework/messaging/rsocket/MetadataEncoder.java

@@ -106,8 +106,7 @@ private static String expand(String route, Object... routeVars) {
 		Matcher matcher = VARS_PATTERN.matcher(route);
 		while (matcher.find()) {
 			Assert.isTrue(index < routeVars.length, () -> "No value for variable '" + matcher.group(1) + "'");
-			String value = routeVars[index].toString();
-			value = value.contains(".") ? value.replaceAll("\\.", "%2E") : value;
+			String value = routeVars[index].toString().replace(".", "%2E");
 			matcher.appendReplacement(sb, value);
 			index++;
 		}