PathPatternParser allows '-' in variables

The isJavaIdentifier check is not really required, but also seems
intuitive for variables to be Java identifier-like. This commit relaxes
the constraint a bit by also allowing "-".

Closes gh-23101

spring-web/src/test/java/org/springframework/web/util/pattern/PathPatternParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -185,6 +185,7 @@ public class PathPatternParserTests {
 		checkStructure("/{foo}");
 		checkStructure("/{f}/");
 		checkStructure("/{foo}/{bar}/{wibble}");
+		checkStructure("/{mobile-number}"); // gh-23101
 	}
 	
 	@Test