patch 8.2.1903: buffer test fails with normal features

Problem:    Buffer test fails with normal features.
Solution:   Use 'numberwidth' instead of 'conceallevel' in the test.
diff --git a/src/version.c b/src/version.c
index c2d6240..9725e9a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1903,
+/**/
     1902,
 /**/
     1901,