Change default of gssEncMode to ALLOW. PostgreSQL can deal with PREFE…

…R but there are cloud providers that did not implement the protocol properly

pgjdbc/src/main/java/org/postgresql/jdbc/GSSEncMode.java

@@ -50,7 +50,7 @@ public static GSSEncMode of(Properties info) throws PSQLException {
     String gssEncMode = PGProperty.GSS_ENC_MODE.get(info);
     // If gssEncMode is not set, fallback to prefer
     if (gssEncMode == null) {
-      return PREFER;
+      return ALLOW;
     }
 
     for (GSSEncMode mode : VALUES) {