Require Jenkins 2.387.3 or newer

Over 90% of the installations of release 1.4 (released a month ago)
are already running Jenkins 2.387.3.

The distribution of installations by release is relatively wide, with 20%
of all installations running release 1.4. About 20% are running release
1.3.0 that was released 6 months ago.  34% of installations of 1.3.0
are on 2.387.3 or newer.

When users upgrade the plugin, they seem to also upgrade to Jenkins
2.387.3 or newer.

https://stats.jenkins.io/pluginversions/docker-plugin.html

pom.xml

@@ -62,7 +62,7 @@
   <properties>
     <revision>1.5</revision>
     <changelist>-SNAPSHOT</changelist>
-    <jenkins.version>2.375.4</jenkins.version>
+    <jenkins.version>2.387.3</jenkins.version>
     <gitHubRepo>jenkinsci/docker-plugin</gitHubRepo>
     <!-- Our unit-tests that talk to a real docker deamon aren't very stable -->
     <surefire.rerunFailingTestsCount>3</surefire.rerunFailingTestsCount>
@@ -76,8 +76,8 @@
     <dependencies>
       <dependency>
         <groupId>io.jenkins.tools.bom</groupId>
-        <artifactId>bom-2.375.x</artifactId>
-        <version>2198.v39c76fc308ca</version>
+        <artifactId>bom-2.387.x</artifactId>
+        <version>2230.v0cb_4040cde55</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>