mark unused vars as errors

Reviewed By: lblasa

Differential Revision: D50500690

fbshipit-source-id: 6f739fe25c232ecfe842337af4399681e85f6a13

desktop/scripts/tsc-plugins.tsx

@@ -16,7 +16,6 @@ import {EOL} from 'os';
 import pmap from 'p-map';
 import {rootDir} from './paths';
 import yargs from 'yargs';
-import {isPluginJson} from 'flipper-common';
 
 const argv = yargs
   .usage('yarn tsc-plugins [args]')