[Integrated] RFR: Add checkout instructions to PR body

[Jorn Vernee]

Changeset: 84a1235c
Author:    Jorn Vernee <jvernee at openjdk.org>
Date:      2020-02-18 12:20:25 +0000
URL:       https://git.openjdk.java.net/skara/commit/84a1235c

Add checkout instructions to PR body

Reviewed-by: ehelin

! bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckRun.java
! bots/pr/src/test/java/org/openjdk/skara/bots/pr/ContributorTests.java