Log Message:
Update to sudo 1.8.31

What's new:

* Fixed CVE-2019-18634, a buffer overflow when the "pwfeedback"
  sudoers option is enabled on systems with uni-directional pipes.

* The "sudoedit_checkdir" option now treats a user-owned directory
  as writable, even if it does not have the write bit set at the
  time of check.  Symbolic links will no longer be followed by
  sudoedit in any user-owned directory.  Bug #912

* Fixed sudoedit on macOS 10.15 and above where the root file system
  is mounted read-only.  Bug #913.

* Fixed a crash introduced in sudo 1.8.30 when suspending sudo
  at the password prompt.  Bug #914.

* Fixed compilation on systems where the mmap MAP_ANON flag
  is not available.  Bug #915.