Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index 2d1446b..857294f 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -1313,7 +1313,7 @@
   norm! 0K
   call assert_equal('version8.txt', fnamemodify(bufname('%'), ':t'))
   call assert_equal('help', &ft)
-  call assert_match('\*version8\.0\*', getline('.'))
+  call assert_match('\*version8\.\d\*', getline('.'))
   helpclose
 
   set keywordprg=:new