Merge pull request #221 from gdcc/renovate/maven-flatten-plugin.version

chore(deps): update dependency org.codehaus.mojo:flatten-maven-plugin to v1.6.0

pom.xml

@@ -71,7 +71,7 @@
         <maven-site-plugin.version>4.0.0-M13</maven-site-plugin.version>
         <maven-source-plugin.version>3.3.0</maven-source-plugin.version>
         <maven-javadoc-plugin.version>3.6.3</maven-javadoc-plugin.version>
-        <maven-flatten-plugin.version>1.5.0</maven-flatten-plugin.version>
+        <maven-flatten-plugin.version>1.6.0</maven-flatten-plugin.version>
         <maven-gpg-plugin.version>3.1.0</maven-gpg-plugin.version>
         <maven-release-plugin.version>3.0.1</maven-release-plugin.version>
         <maven-enforcer-plugin.version>3.4.1</maven-enforcer-plugin.version>