[Integrated] RFR: csr bot: use pull request cache

[Erik Helin]

Changeset: 88db8fad
Author:    Erik Helin <ehelin at openjdk.org>
Date:      2020-02-18 13:52:30 +0000
URL:       https://git.openjdk.java.net/skara/commit/88db8fad

csr bot: use pull request cache

Reviewed-by: rwestberg

! bots/csr/src/main/java/org/openjdk/skara/bots/csr/CSRBot.java