chore(build): remove deprecated dep

Author: amejiarosario

Diff for: .circleci/config.yml

@@ -84,7 +84,7 @@ jobs: # a collection of steps
 
       - run:
           name: Bundle Install.pre - needed for mathematical -> 'asciidoctor-mathematical' gem
-          command: sudo apt-get -qq -y install cmake bison flex libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev libpango1.0-dev ttf-lyx
+          command: sudo apt-get -qq -y install cmake bison flex libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev libpango1.0-dev
 
       - run:
           name: Bundle Install.pre - install GraphicsMagick for 'prawn-gmagick' gem