Replace kotlin stdlib jre7 to jdk7

[chibatching]

Issue

• no issue

Overview (Required)

• Replace deprecated kotlin-stdlib-jre7 to kotlin-stdlib-jdk7

Links

• https://discuss.kotlinlang.org/t/kotlin-standard-library-jre-7-8-extensions/3715/4
• https://kotlinlang.org/docs/reference/whatsnew12.html#kotlin-standard-library-artifacts-and-split-packages

Screenshot

Before	After

[takahirom]

LGTM 👍

[jmatsu]

LGTM 🎉