SystemJS 0.20.18

Bug Fixes

• Updates ESM regex detection not to detect flow type comments (eacc8c8, #1721)
• Updates package configuration detection bug (0f05dbf, #1658)
• Allows fetch-only plugins to run through translate (#1727, thanks to @felixrabe)
• Falsy __useDefault interop fix from ES Module Loader 2.2.7 (af128f6, ModuleLoader/es-module-loader@31de1f5)