bumped quickjs to release 2020-09-06 and sitched to using the official github mirror for quickjs source

Author: goodlyrottenapple

quickjs-hs.cabal

@@ -19,7 +19,6 @@ description:
     .
     To get started, see the ReadMe below.
 
-
 extra-source-files:
     quickjs/cutils.h
   , quickjs/libbf.h
@@ -31,7 +30,6 @@ extra-source-files:
   , quickjs/quickjs-atom.h
   , quickjs/quickjs-opcode.h
 
-
 source-repository head
   type: git
   location: https://github.com/goodlyrottenapple/quickjs-hs