Bump version for zstd support to 6.3 (first defined in appnote 6.3.7).
diff --git a/lib/zip_algorithm_zstd.c b/lib/zip_algorithm_zstd.c
index 02d910c..6676c29 100644
--- a/lib/zip_algorithm_zstd.c
+++ b/lib/zip_algorithm_zstd.c
@@ -216,7 +216,7 @@
     compress_allocate,
     deallocate,
     general_purpose_bit_flags,
-    20,
+    63,
     start,
     end,
     input,
@@ -229,7 +229,7 @@
     decompress_allocate,
     deallocate,
     general_purpose_bit_flags,
-    20,
+    63,
     start,
     end,
     input,