putty: update to 0.80.

PuTTY version 0.80 is released
------------------------------

This is a SECURITY UPDATE. We recommend that _everybody_ upgrade, as
soon as possible.

There is one security fix in this release:

 - Fix for a newly discovered security issue known as the 'Terrapin'
   attack, also numbered CVE-2023-48795. The issue affects widely-used
   OpenSSH extensions to the SSH protocol: the ChaCha20+Poly1305
   cipher system, and 'encrypt-then-MAC' mode.

   In order to benefit from the fix, you must be using a fixed version
   of PuTTY _and_ a server with the fix, so that they can agree to
   adopt a modified version of the protocol. Alternatively, you may be
   able to reconfigure PuTTY to avoid selecting any of the affected
   modes.

   If PuTTY 0.80 connects to an SSH server without the fix, it will
   warn you if the initial protocol negotiation chooses an insecure
   mode to run the connection in, so that you can abandon the
   connection. If it's possible to alter PuTTY's configuration to
   avoid the problem, then the warning message will tell you how to do
   it.

As well as this security fix, there are two other ordinary bug fixes
in 0.80:

 - On Windows, if you installed the MSI package, PuTTY could not find
   its help file. The help file was installed, but PuTTY wouldn't be
   able to open it, so the help buttons in its dialog boxes were
   missing.

 - Sometimes, if you were looking at the terminal scrollback, the view
   position would be reset to the bottom of the scrollback unwantedly,
   if the server sent terminal output that didn't actually cause
   anything to be printed.


(wiz)