[yocto-security] Should dropbear ssh disallow SHA1

[Joseph Reynolds]

The OpenBMC project [1] uses Yocto/poky, including the dropbear ssh 
server.  We are changing the default ciphers offered by dropbear to 
disallow SHA1, because we believe this level of security is correct for 
our project.  The change is currently in code review [2].

Would you like to make this change or a similar change in Yocto/poky?  
Even if doing so might break compatibility with older ssh clients?  See 
our code review [2] for considerations.

- Joseph

[1]: github.com/openbmc/openbmc
[2]: https://gerrit.openbmc-project.xyz/c/openbmc/meta-phosphor/+/21028