Bump acorn from 7.1.0 to 7.3.1

Bumps [acorn](https://github.com/acornjs/acorn) from 7.1.0 to 7.3.1.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/7.1.0...7.3.1)

Signed-off-by: dependabot[bot] <support@github.com>

yarn.lock

@@ -78,9 +78,9 @@ acorn-jsx@^5.1.0:
   integrity sha512-tMUqwBWfLFbJbizRmEcWSLw6HnFzfdJs2sOJEOwwtVPMoH/0Ay+E703oZz78VSXZiiDcZrQ5XKjPIUQixhmgVw==
 
 acorn@^7.1.0:
-  version "7.1.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.1.0.tgz#949d36f2c292535da602283586c2477c57eb2d6c"
-  integrity sha512-kL5CuoXA/dgxlBbVrflsflzQ3PAas7RYZB52NOm/6839iVYJgKMJ3cQJD+t2i5+qFa8h3MDpEOJiS64E8JLnSQ==
+  version "7.3.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.3.1.tgz#85010754db53c3fbaf3b9ea3e083aa5c5d147ffd"
+  integrity sha512-tLc0wSnatxAQHVHUapaHdz72pi9KUyHjq5KyHjGg9Y8Ifdc79pTh2XvI6I1/chZbnM7QtNKzh66ooDogPZSleA==
 
 ajv@^6.10.0, ajv@^6.10.2:
   version "6.10.2"