CSharp compiler: fix role (#105)

Co-authored-by: Michal Růžička <michal.ruzicka@aimtecglobal.com>

Author: mruzicka

plexus-compilers/plexus-compiler-csharp/src/main/java/org/codehaus/plexus/compiler/csharp/CSharpCompiler.java

@@ -17,6 +17,7 @@
  */
 
 import org.codehaus.plexus.compiler.AbstractCompiler;
+import org.codehaus.plexus.compiler.Compiler;
 import org.codehaus.plexus.compiler.CompilerConfiguration;
 import org.codehaus.plexus.compiler.CompilerException;
 import org.codehaus.plexus.compiler.CompilerMessage;