Remove obsolete import

Author: michael-o

src/main/java/org/codehaus/plexus/archiver/jar/Manifest.java

@@ -21,7 +21,6 @@
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.PrintWriter;
 import java.io.Reader;
 import java.io.StringWriter;
 import java.io.Writer;