patch 9.0.1430: Livebook files are not recognized

Problem:    Livebook files are not recognized.
Solution:   Add a pattern for Livebook files. (Mathias Jean Johansen,
            closes #12203)
diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index a286717..56df5d6 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -1162,6 +1162,9 @@
 " LiteStep RC files
 au BufNewFile,BufRead */LiteStep/*/*.rc		setf litestep
 
+" Livebook
+au BufNewFile,BufRead *.livemd			setf livebook
+
 " Login access
 au BufNewFile,BufRead */etc/login.access	setf loginaccess
 
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 2ae36b3..a753ec8 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -336,6 +336,7 @@
     \ 'lite': ['file.lite', 'file.lt'],
     \ 'litestep': ['/LiteStep/any/file.rc', 'any/LiteStep/any/file.rc'],
     \ 'logcheck': ['/etc/logcheck/file.d-some/file', '/etc/logcheck/file.d/file', 'any/etc/logcheck/file.d-some/file', 'any/etc/logcheck/file.d/file'],
+    \ 'livebook': ['file.livemd'],
     \ 'loginaccess': ['/etc/login.access', 'any/etc/login.access'],
     \ 'logindefs': ['/etc/login.defs', 'any/etc/login.defs'],
     \ 'logtalk': ['file.lgt'],
diff --git a/src/version.c b/src/version.c
index 23e69b3..ee7b363 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1430,
+/**/
     1429,
 /**/
     1428,