patch 9.0.0424: gitattributes files are not recognized

Problem:    gitattributes files are not recognized.
Solution:   Add patterns to match gitattributes files. (closes #11085)
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 33b0894..b70a9fe 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -213,6 +213,7 @@
     \ 'gedcom': ['file.ged', 'lltxxxxx.txt', '/tmp/lltmp', '/tmp/lltmp-file', 'any/tmp/lltmp', 'any/tmp/lltmp-file'],
     \ 'gemtext': ['file.gmi', 'file.gemini'],
     \ 'gift': ['file.gift'],
+    \ 'gitattributes': ['file.git/info/attributes', '.gitattributes', '/.config/git/attributes', '/etc/gitattributes', '/usr/local/etc/gitattributes', 'some.git/info/attributes'],
     \ 'gitcommit': ['COMMIT_EDITMSG', 'MERGE_MSG', 'TAG_EDITMSG', 'NOTES_EDITMSG', 'EDIT_DESCRIPTION'],
     \ 'gitconfig': ['file.git/config', 'file.git/config.worktree', 'file.git/worktrees/x/config.worktree', '.gitconfig', '.gitmodules', 'file.git/modules//config', '/.config/git/config', '/etc/gitconfig', '/usr/local/etc/gitconfig', '/etc/gitconfig.d/file', 'any/etc/gitconfig.d/file', '/.gitconfig.d/file', 'any/.config/git/config', 'any/.gitconfig.d/file', 'some.git/config', 'some.git/modules/any/config'],
     \ 'gitolite': ['gitolite.conf', '/gitolite-admin/conf/file', 'any/gitolite-admin/conf/file'],
diff --git a/src/version.c b/src/version.c
index 445ac6d..24c99fd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -704,6 +704,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    424,
+/**/
     423,
 /**/
     422,