PDFBOX-5660: update picocli

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1917569 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index d8dafbc..9b61d86 100644
--- a/pom.xml
+++ b/pom.xml
@@ -61,7 +61,7 @@
     <jbig2.version>3.0.4</jbig2.version>
     <jai.version>1.4.0</jai.version>
     <commons-io.version>2.16.1</commons-io.version>
-    <picocli.version>4.7.5</picocli.version>
+    <picocli.version>4.7.6</picocli.version>
     <!-- This is a default value to avoid problems when running single tests
           see also https://stackoverflow.com/a/28695766/535646
           https://maven.apache.org/surefire/maven-surefire-plugin/faq.html#late-property-evaluation