Appveyor: Fix typo in appveyor.yml.
Appveyor: Fix typo in appveyor.yml.

Added a missing 'p' to .zip file.

ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz