git: openjdk/shenandoah-visualizer: master: Update README.md

[duke]

Changeset: ffb924a6
Author:    Aleksey Shipilëv <shade at redhat.com>
Committer: GitHub <noreply at github.com>
Date:      2020-11-16 19:34:23 +0000
URL:       https://github.com/openjdk/shenandoah-visualizer/commit/ffb924a6

Update README.md

! README.md