security/sudo: update to 1.9.7

Among other changes this release fixes -fcommon errors. A complete list
of changes can be found at https://www.sudo.ws/stable.html/

PR: 255812
Submitted by: Yasuhiro Kimura <yasu@utahime.org> (mostly)
Reported by: Yasuhiro Kimura <yasu@utahime.org>
Tested by: cy
Approved by: garga (maintainer)
MFH: 2021Q2