Require Jenkins 2.440.3 or newer

https://stats.jenkins.io/pluginversions/promoted-builds.html shows that
85% of the installations of the most recent release (delivered 3 months
ago) are already running Jenkins 2.440.3 or newer.  Users that are
upgrading to the most recent release of the plugin are also upgrading
to the most recent Jenkins releases.

Removes unnecessary declarations of mockito-core and hamcrest since
those are provided by the parent pom.

Removes unnecessary exclusions from other dependencies.

pom.xml

@@ -18,7 +18,7 @@
   <properties>
     <changelist>999999-SNAPSHOT</changelist>
     <gitHubRepo>jenkinsci/${project.artifactId}-plugin</gitHubRepo>
-    <jenkins.version>2.387.3</jenkins.version>
+    <jenkins.version>2.440.3</jenkins.version>
     <spotbugs.effort>Max</spotbugs.effort>
     <hpi.compatibleSinceVersion>4.0</hpi.compatibleSinceVersion>
   </properties>
@@ -68,8 +68,8 @@
     <dependencies>
       <dependency>
         <groupId>io.jenkins.tools.bom</groupId>
-        <artifactId>bom-2.387.x</artifactId>
-        <version>2543.vfb_1a_5fb_9496d</version>
+        <artifactId>bom-2.440.x</artifactId>
+        <version>3289.v3ff9637cd241</version>
         <scope>import</scope>
         <type>pom</type>
       </dependency>
@@ -81,12 +81,6 @@
       <groupId>org.jenkins-ci.main</groupId>
       <artifactId>maven-plugin</artifactId>
       <optional>true</optional>
-      <exclusions>
-        <exclusion>
-          <groupId>commons-net</groupId>
-          <artifactId>commons-net</artifactId>
-        </exclusion>
-      </exclusions>
     </dependency>
     <dependency>
       <groupId>org.jenkins-ci.plugins</groupId>
@@ -105,16 +99,6 @@
       <groupId>org.jenkins-ci.plugins</groupId>
       <artifactId>structs</artifactId>
     </dependency>
-    <dependency>
-      <groupId>org.hamcrest</groupId>
-      <artifactId>hamcrest</artifactId>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>org.mockito</groupId>
-      <artifactId>mockito-core</artifactId>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>org.jenkins-ci.plugins</groupId>
       <artifactId>token-macro</artifactId>
@@ -133,12 +117,6 @@
       <artifactId>job-dsl</artifactId>
       <version>1.87</version>
       <optional>true</optional>
-      <exclusions>
-        <exclusion>
-          <groupId>org.codehaus.groovy</groupId>
-          <artifactId>groovy-all</artifactId>
-        </exclusion>
-      </exclusions>
     </dependency>
     <dependency>
       <groupId>org.jenkins-ci.plugins</groupId>
@@ -150,7 +128,7 @@
       <optional>true</optional>
     </dependency>
     <dependency>
-      <!-- TODO: it is something insane, no? -->
+      <!-- Needed for Job DSL test -->
       <groupId>org.jenkins-ci.plugins</groupId>
       <artifactId>parameterized-trigger</artifactId>
       <scope>test</scope>