Update httpcore.version to v5.3.1

Author: renovate[bot]

pom.xml

@@ -44,7 +44,7 @@
   <properties>
     <gitHubRepo>jenkinsci/apache-httpcomponents-client-5-api-plugin</gitHubRepo>
     <httpclient.version>5.4</httpclient.version>
-    <httpcore.version>5.3</httpcore.version>
+    <httpcore.version>5.3.1</httpcore.version>
     <jenkins.version>2.361.4</jenkins.version>
     <revision>${httpclient.version}</revision>
     <changelist>999999-SNAPSHOT</changelist>