dropbear: bump version

dropbear: bump version

Fixes two security issues:

- The Dropbear server could be made to consume large amounts
of memory because decompressed packet sizes weren't checked.
Depending on the OS and hardware this might be a denial of
service.

- Valid users could be identified due to timing variations.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>