Update dependency org.sonatype.plugins:nexus-staging-maven-plugin to v1.6.8 (#18)

Co-authored-by: Renovate Bot <[email protected]>

Author: renovate[bot]

pom.xml

@@ -45,7 +45,7 @@
         <javadoc-plugin.version>3.2.0</javadoc-plugin.version>
         <gpg-plugin.version>1.6</gpg-plugin.version>
         <versions-plugin.version>2.8.1</versions-plugin.version>
-        <nexus-staging-plugin.version>1.6.7</nexus-staging-plugin.version>
+        <nexus-staging-plugin.version>1.6.8</nexus-staging-plugin.version>
     </properties>
 
     <modules>