Summary: To be able to save min required Flipper version into the package.json, we need to ignore it when computing hashsum. Otherwise hashsum of plugin will depend on the current Flipper version and so bumping Flipper will change hashsums of all plugins.
Reviewed By: passy
Differential Revision: D28342965
fbshipit-source-id: 289ec7e673bce1f2b1cbb402b56c5b1b31fd84da