[java] add deprecation annotation to FirefoxBinary

Author: titusfortner

java/src/org/openqa/selenium/firefox/FirefoxBinary.java

@@ -44,6 +44,7 @@
  * @deprecated Use {@link FirefoxOptions#setBinary(Path)} or {@link
  *     FirefoxOptions#setBinary(String)} instead.
  */
+@Deprecated
 public class FirefoxBinary {
 
   /** Enumerates Firefox channels, according to https://wiki.mozilla.org/RapidRelease */