chore: bump ls protocol version to 18 (#252)

Author: ShawkyZ

plugin/src/main/java/io/snyk/languageserver/download/LsBinaries.java

@@ -8,7 +8,7 @@
 
 public class LsBinaries {
   private static final Preferences PREFERENCES = Preferences.getInstance();
-  public static final String REQUIRED_LS_PROTOCOL_VERSION = "17";
+  public static final String REQUIRED_LS_PROTOCOL_VERSION = "18";
 
   public static URI getBaseUri() {
     return URI.create(PREFERENCES.getPref(CLI_BASE_URL));