[DOXIATOOLS-63] Upgrade plexus-container-default to 2.1.0

diff --git a/pom.xml b/pom.xml
index 2691ae7..fb1c219 100644
--- a/pom.xml
+++ b/pom.xml
@@ -67,6 +67,11 @@
         <artifactId>plexus-utils</artifactId>
         <version>3.3.0</version>
       </dependency>
+      <dependency>
+        <groupId>org.codehaus.plexus</groupId>
+        <artifactId>plexus-container-default</artifactId>
+        <version>2.1.0</version>
+      </dependency>
     </dependencies>
   </dependencyManagement>
   <dependencies>
diff --git a/src/main/java/org/apache/maven/doxia/DefaultConverter.java b/src/main/java/org/apache/maven/doxia/DefaultConverter.java
index d63458b..f4b5ef7 100644
--- a/src/main/java/org/apache/maven/doxia/DefaultConverter.java
+++ b/src/main/java/org/apache/maven/doxia/DefaultConverter.java
@@ -499,7 +499,7 @@
             return;
         }
 
-        Map<String, String> context = new HashMap<>();
+        Map<Object, Object> context = new HashMap<>();
         context.put( "basedir", new File( "" ).getAbsolutePath() );
 
         ContainerConfiguration containerConfiguration = new DefaultContainerConfiguration();