Bump cobertura-maven-plugin from 2.4 to 2.7

Bumps cobertura-maven-plugin from 2.4 to 2.7.

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index a7c378e..b4382d6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -249,7 +249,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>cobertura-maven-plugin</artifactId>
-        <version>2.4</version>
+        <version>2.7</version>
       </plugin>
     </plugins>
   </reporting>