ubuntu package dependencies updated

won't build without libxml-parser-perl under ubuntu 16.04 on ppc64le

Signed-off-by: Peter Kowalsky <peter@kowalsky.at>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
diff --git a/README.md b/README.md
index aa99174..d19cff1 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@
         sudo apt-get install cscope ctags libz-dev libexpat-dev \
           python language-pack-en texinfo \
           build-essential g++ git bison flex unzip \
-          libssl-dev libxml-simple-perl libxml-sax-perl libxml2-dev libxml2-utils xsltproc \
+          libssl-dev libxml-simple-perl libxml-sax-perl libxml-parser-perl libxml2-dev libxml2-utils xsltproc \
           wget bc
 
 ### Dependencies for *64-bit* Fedora systems