closurecompiler: 20180506 -> 20180610

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/closure-compiler/versions.

These checks were done:

- built on NixOS
- /nix/store/7mbi0qnqknb3z96a4af1p8wyyi0jf2q5-closure-compiler-20180610/bin/closure-compiler passed the binary check.
- 1 of 1 passed binary check by having a zero exit code.
- 0 of 1 passed binary check by having the new version present in output.
- found 20180610 with grep in /nix/store/7mbi0qnqknb3z96a4af1p8wyyi0jf2q5-closure-compiler-20180610
- directory tree listing: https://gist.github.com/2841b8a1c31feea2745c98e5234d70c3
- du listing: https://gist.github.com/e36999cb96d2e1b1366f7bd1c3804cad