Use jenkins.baseline to reduce bom update mistakes (#128)

Author: strangelookingnerd

pom.xml

@@ -20,8 +20,10 @@
     <revision>1.19</revision>
     <changelist>-SNAPSHOT</changelist>
     <gitHubRepo>jenkinsci/${project.artifactId}-plugin</gitHubRepo>
-    <jenkins.version>2.361.4</jenkins.version>
-    <bom>2.361.x</bom>
+    <!-- https://www.jenkins.io/doc/developer/plugin-development/choosing-jenkins-baseline/ -->
+    <jenkins.baseline>2.361</jenkins.baseline>
+    <jenkins.version>${jenkins.baseline}.4</jenkins.version>
+    <bom>${jenkins.baseline}.x</bom>
     <bom.version>2102.v854b_fec19c92</bom.version>
   </properties>