chore(package): update acorn-es7-plugin to 1.0.10 and stop pinning of acorn version
chore(package): update acorn-es7-plugin to 1.0.10 and stop pinning of acorn version

refs: https://github.com/power-assert-js/power-assert-formatter/pull/20#issuecomment-163698045

power-assert-js/power-assert-formatter,power-assert-js/power-assert-formatter