[Integrated] RFR: Post the incremental webrev url in the PR comment

[Robin Westberg]

Changeset: 9f56fcae
Author:    Robin Westberg <rwestberg at openjdk.org>
Date:      2020-01-20 14:23:34 +0000
URL:       https://git.openjdk.java.net/skara/commit/9f56fcae

Post the incremental webrev url in the PR comment

Reviewed-by: ehelin

! bots/mlbridge/src/main/java/org/openjdk/skara/bots/mlbridge/ArchiveItem.java
! bots/mlbridge/src/main/java/org/openjdk/skara/bots/mlbridge/ArchiveWorkItem.java
! bots/mlbridge/src/main/java/org/openjdk/skara/bots/mlbridge/WebrevNotification.java
! bots/mlbridge/src/test/java/org/openjdk/skara/bots/mlbridge/MailingListBridgeBotTests.java