Modernize plugin

Jenkinsfile

@@ -1,12 +1,4 @@
-#!/usr/bin/env groovy
-
-buildPlugin(useContainerAgent: false, // temporarily disable for Windows issues
-        configurations: [
-                [platform: 'linux', jdk: '11'],
-                [platform: 'windows', jdk: '8'],
-
-                // testing the Guava & Guice bumps
-                // https://github.com/jenkinsci/jenkins/pull/5707
-                // https://github.com/jenkinsci/jenkins/pull/5858
-                //[ platform: "linux", jdk: "8", jenkins: '2.321', javaLevel: "8" ]
-        ])
+buildPlugin(configurations: [
+  [platform: 'linux', jdk: 17],
+  [platform: 'windows', jdk: 11],
+])

pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>org.jenkins-ci.plugins</groupId>
     <artifactId>plugin</artifactId>
-    <version>4.51</version>
+    <version>4.63</version>
     <relativePath />
   </parent>
 
@@ -18,7 +18,7 @@
   <properties>
     <changelist>999999-SNAPSHOT</changelist>
     <gitHubRepo>jenkinsci/${project.artifactId}-plugin</gitHubRepo>
-    <jenkins.version>2.319.3</jenkins.version>
+    <jenkins.version>2.361.4</jenkins.version>
     <findbugs.effort>Max</findbugs.effort>
     <hpi.compatibleSinceVersion>4.0</hpi.compatibleSinceVersion>
   </properties>
@@ -68,8 +68,8 @@
     <dependencies>
       <dependency>
         <groupId>io.jenkins.tools.bom</groupId>
-        <artifactId>bom-2.319.x</artifactId>
-        <version>1654.vcb_69d035fa_20</version>
+        <artifactId>bom-2.361.x</artifactId>
+        <version>2081.v85885a_d2e5c5</version>
         <scope>import</scope>
         <type>pom</type>
       </dependency>

src/main/java/hudson/plugins/promoted_builds/PromotionProcess.java

@@ -652,7 +652,8 @@ public FormValidation doCheckLabelString(@QueryParameter String value) {
                         Messages.JobPropertyImpl_LabelString_InvalidBooleanExpression(e.getMessage()));
             }
             // TODO: if there's an atom in the expression that is empty, report it
-            if (Jenkins.get().getLabel(value).isEmpty())
+            Label label = Jenkins.get().getLabel(value);
+            if (label == null || label.isEmpty())
                 return FormValidation.warning(Messages.JobPropertyImpl_LabelString_NoMatch());
             return FormValidation.ok();
         }