Upgrade maven-gpg-plugin 3.2.7 -> 3.2.8

See:
- apache/maven-gpg-plugin@maven-gpg-plugin-3.2.7...maven-gpg-plugin-3.2.8

Author: Picnic-DevPla-Bot

pom.xml

@@ -1153,7 +1153,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-gpg-plugin</artifactId>
-                    <version>3.2.7</version>
+                    <version>3.2.8</version>
                     <executions>
                         <execution>
                             <id>sign-artifacts</id>