Ignore SCM API 2.0 related changes until the cause of JENKINS-41121

The basic idea of this is that the upgrades are sufficiently dangerous and *one
direction* (i.e. no rollback except for restoring from a pre-upgrade backup of
JENKINS_HOME) that it's best for Jenkins users to hide these versions until this
is figured out and made more safe.

See https://jenkins.io/blog/2017/01/17/scm-api-2/ for the list of affected
plugins.

src/main/resources/artifact-ignores.properties

@@ -118,3 +118,16 @@ scm-api-2.0
 # Suppress Scala Hello World Plugin (HOSTING-235)
 hello-world-scala
 
+
+# Suppress potentially harmful upgrades related to SCM API (JENKINS-41121)
+# Erring on the side of extreme caution until the fallout is resolved here
+scm-api:2.0.0
+scm-api:2.0.1
+branch-api:2.0.0
+github-branch-source:2.0.0
+cloudbees-bitbucket-branch-source:2.0.0
+github-organization-folder:1.6
+mercurial:1.58
+git:2.6.2
+git:3.0.2
+git:3.0.3