patch 8.1.0970: text properties test fails when 'encoding' is not utf-8

Problem:    Text properties test fails when 'encoding' is not utf-8.
Solution:   Compare with original value of 'encoding'. (Christian Brabandt,
            closes #3986)
diff --git a/src/version.c b/src/version.c
index cd45fa0..c4034ee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    970,
+/**/
     969,
 /**/
     968,