patch 8.1.0498: /etc/gitconfig not recognized at a gitconfig file

Problem:    /etc/gitconfig not recognized at a gitconfig file.
Solution:   Add pattern to filetype detection. (closes #3568)
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 3240f1f..9c53764 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -171,7 +171,7 @@
     \ 'gdmo': ['file.mo', 'file.gdmo'],
     \ 'gedcom': ['file.ged', 'lltxxxxx.txt'],
     \ 'gitcommit': ['COMMIT_EDITMSG', 'MERGE_MSG', 'TAG_EDITMSG'],
-    \ 'gitconfig': ['file.git/config', '.gitconfig', '.gitmodules', 'file.git/modules//config', '/.config/git/config'],
+    \ 'gitconfig': ['file.git/config', '.gitconfig', '.gitmodules', 'file.git/modules//config', '/.config/git/config', '/etc/gitconfig'],
     \ 'gitolite': ['gitolite.conf'],
     \ 'gitrebase': ['git-rebase-todo'],
     \ 'gitsendemail': ['.gitsendemail.msg.xxxxxx'],
diff --git a/src/version.c b/src/version.c
index c3f2e23..c867ecf 100644
--- a/src/version.c
+++ b/src/version.c
@@ -793,6 +793,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    498,
+/**/
     497,
 /**/
     496,