chore: Set LS Protocol version to 9 (#140)

Set LS Protocol version to 9

Author: Asaf Agami

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

@@ -4,7 +4,7 @@
 
 public class LsBinaries {
   private static final String LS_DOWNLOAD_BASE_URL = "https://static.snyk.io/snyk-ls";
-  public static final String REQUIRED_LS_PROTOCOL_VERSION = "10";
+  public static final String REQUIRED_LS_PROTOCOL_VERSION = "9";
 
   public static URI getBaseUri() {
     return URI.create(String.format("%s/%s", LS_DOWNLOAD_BASE_URL, REQUIRED_LS_PROTOCOL_VERSION));