de-bump to sbt 1.9.7 (backport #3852) (#3854)

* debump to sbt 1.9.7 (#3852)

(cherry picked from commit 0c9ebccf

)

# Conflicts:
#	docs/src/installation.md

* Delete docs/src/installation.md

---------

Co-authored-by: Deborah Soung <debs@sifive.com>
Co-authored-by: Jack Koenig <koenig@sifive.com>