patch 8.1.2352: CI doesn't cover FreeBSD

Problem:    CI doesn't cover FreeBSD.
Solution:   Configure Cirrus-CI. (Christian Brabandt, closes #5273)

.cirrus.yml

@@ -0,0 +1,9 @@
+freebsd_12_task:
+  freebsd_instance:
+    image: freebsd-12-1-release-amd64
+  install_script:
+    pkg install -y gettext gmake
+  build_script:
+    - gmake
+  test_script:
+    - gmake test

README.md

@@ -2,6 +2,7 @@
 
 [![Build Status](https://travis-ci.org/vim/vim.svg?branch=master)](https://travis-ci.org/vim/vim)
 [![Appveyor Build status](https://ci.appveyor.com/api/projects/status/o2qht2kjm02sgghk?svg=true)](https://ci.appveyor.com/project/chrisbra/vim)
+[![Build Status](https://api.cirrus-ci.com/github/chrisbra/vim.svg)](https://cirrus-ci.com/github/chrisbra/vim)
 [![Coverage Status](https://codecov.io/gh/vim/vim/coverage.svg?branch=master)](https://codecov.io/gh/vim/vim?branch=master)
 [![Coverity Scan](https://scan.coverity.com/projects/241/badge.svg)](https://scan.coverity.com/projects/vim)
 [![Language Grade: C/C++](https://img.shields.io/lgtm/grade/cpp/g/vim/vim.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/vim/vim/context:cpp)

src/version.c

@@ -737,6 +737,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2352,
 /**/
     2351,
 /**/