only lint stashed lines

git hooks will lint only staged lines
dont use with `--fix` as it can create conflicts
(see lint-staged/lint-staged#62)

Should provide a better DX: one may now commit a file with non staged
lines without having lint complain about unstaged lines

scripts/lint_staged

@@ -11,6 +11,8 @@ else
   if [ "$1" = "fix"  ] || [ "$1" = "--fix" ]; then
     echo $staged | xargs npm run lint-fix
   else
+    git stash -k
     echo $staged | xargs npm run lint
+    git stash pop -q
   fi
 fi