chore(package): update phantomjs-prebuilt to version 2.1.8
chore(package): update phantomjs-prebuilt to version 2.1.8

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Jenselme/ngeo,camptocamp/ngeo,adube/ngeo,adube/ngeo,ger-benjamin/ngeo,camptocamp/ngeo,camptocamp/ngeo,kalbermattenm/ngeo,camptocamp/ngeo,adube/ngeo,ger-benjamin/ngeo,kalbermattenm/ngeo,kalbermattenm/ngeo,camptocamp/ngeo,Jenselme/ngeo,Jenselme/ngeo,Jenselme/ngeo,ger-benjamin/ngeo,adube/ngeo