ci: fix call -> cmd /c on appveyor
ci: fix call -> cmd /c on appveyor

JCMais/node-libcurl,JCMais/node-libcurl,JCMais/node-libcurl,JCMais/node-libcurl,JCMais/node-libcurl,JCMais/node-libcurl,JCMais/node-libcurl