Feat: support idleMinutes field in pipeline

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/PodTemplateStep.java

@@ -41,6 +41,8 @@ public class PodTemplateStep extends Step implements Serializable {
     private List<PodAnnotation> annotations = new ArrayList<>();
 
     private int instanceCap;
+    private int idleMinutes;
+
     private String serviceAccount;
     private String nodeSelector;
     private String workingDir = ContainerTemplate.DEFAULT_WORKING_DIR;
@@ -122,6 +124,15 @@ public void setInstanceCap(int instanceCap) {
         this.instanceCap = instanceCap;
     }
 
+    public int getIdleMinutes() {
+        return idleMinutes;
+    }
+
+    @DataBoundSetter
+    public void setIdleMinutes(int idleMinutes) {
+        this.idleMinutes = idleMinutes;
+    }
+
     public String getServiceAccount() {
         return serviceAccount;
     }

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/PodTemplateStepExecution.java

@@ -59,6 +59,7 @@ public boolean start() throws Exception {
         newTemplate.setNamespace(namespace);
         newTemplate.setInheritFrom(!Strings.isNullOrEmpty( podTemplateAction.getParentTemplates()) ? podTemplateAction.getParentTemplates() : step.getInheritFrom());
         newTemplate.setInstanceCap(step.getInstanceCap());
+        newTemplate.setIdleMinutes(step.getIdleMinutes());
         newTemplate.setLabel(step.getLabel());
         newTemplate.setVolumes(step.getVolumes());
         newTemplate.setCustomWorkspaceVolumeEnabled(step.getWorkspaceVolume() != null);

src/main/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/PodTemplateStep/config.jelly

@@ -37,7 +37,10 @@
         <f:entry field="instanceCap" title="${%Max number of instances}">
           <f:textbox default="0"/>
         </f:entry>
-		<f:entry field="serviceAccount" title="The service account">
+        <f:entry field="idleMinutes" title="${%Time in minutes to retain slave when idle}">
+          <f:textbox default="0"/>
+        </f:entry>
+        <f:entry field="serviceAccount" title="The service account">
           <f:textbox/>
         </f:entry>
         <f:entry field="nodeSelector" title="The node selector">

src/main/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/PodTemplateStep/help-idleMinutes.html

@@ -0,0 +1,17 @@
+<!--
+  ~ Copyright (C) 2015 Original Authors
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~         http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+Time in minutes to retain slave when idle