Update to newer version of ghp-import #2170
Description
Currently we are using a vendored (and modified) copy of ghp-import. Recently version 1.0.0 of the package has been released which includes the changes in c-w/ghp-import#69. That makes it possible to call ghp-import directly from Python without the modifications in our vendored copy. Therefore we should consider removing our vendored copy and and ghp-import=1.0 to our list of dependencies.