mdadm: Update version from 3.3.4 to 4.0

This version documents the switch `--write-journal`.

```
       --write-journal
              Specify  journal  device  for  the RAID-4/5/6 array. The journal device should be a SSD
              with reasonable lifetime.
```

Announcement [2]:

> Subject: ANNOUNCE: mdadm 4.0 - A tool for managing md Soft RAID under Linux
>
> I am pleased to announce the availability of
>    mdadm version 4.0
>
> It is available at the usual places:
>    https://www.kernel.org/pub/linux/utils/raid/mdadm/
> and via git at
>    git://git.kernel.org/pub/scm/utils/mdadm/mdadm.git
>    https://git.kernel.org/cgit/utils/mdadm/
>
> The update in major version number primarily indicates this is a
> release by it's new maintainer. In addition it contains a large number
> of fixes in particular for IMSM RAID and clustered RAID support.  In
> addition this release includes support for IMSM 4k sector drives,
> failfast and better documentation for journaled RAID.
>
> This is my first release of mdadm. Please thank Neil Brown for his
> previous work as maintainer and blame me for all the bugs I caused
> since taking over.
>
> Jes Sorensen, 2017-01-09

[1] http://www.linuxfromscratch.org/blfs/view/8.0/postlfs/mdadm.html
[2] https://git.kernel.org/pub/scm/utils/mdadm/mdadm.git/tree/ANNOUNCE-4.0

mdadm.be0

@@ -1,6 +1,6 @@
 #!/usr/bin/env beesh
 
-# BEE_VERSION mdadm-3.3.4-0
+# BEE_VERSION mdadm-4.0-0
 
 ## The source URL(s) array
 SRCURL[0]="https://www.kernel.org/pub/linux/utils/raid/mdadm/mdadm-${PKGVERSION}.tar.xz"