Bump acorn from 6.1.1 to 6.4.1 (#105)

Bumps [acorn](https://github.com/acornjs/acorn) from 6.1.1 to 6.4.1.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](acornjs/acorn@6.1.1...6.4.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

yarn.lock

@@ -768,9 +768,9 @@ acorn-jsx@^5.0.0:
   integrity sha512-HJ7CfNHrfJLlNTzIEUTj43LNWGkqpRLxm3YjAlcD0ACydk9XynzYsCBHxut+iqt+1aBXkx9UP/w/ZqMr13XIzg==
 
 acorn@^6.0.7:
-  version "6.1.1"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.1.1.tgz#7d25ae05bb8ad1f9b699108e1094ecd7884adc1f"
-  integrity sha512-jPTiwtOxaHNaAPg/dmrJ/beuzLRnXtB0kQPQ8JpotKJgTB6rX6c8mlf315941pyjBSaPg8NHXS9fhP4u17DpGA==
+  version "6.4.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.4.1.tgz#531e58ba3f51b9dacb9a6646ca4debf5b14ca474"
+  integrity sha512-ZVA9k326Nwrj3Cj9jlh3wGFutC2ZornPNARZwsNYqQYgN0EsV2d53w5RN/co65Ohn4sUAUtb1rSUAOD6XN9idA==
 
 ajv@^6.9.1:
   version "6.10.0"
@@ -916,7 +916,7 @@ atob@^2.1.1:
   resolved "https://registry.yarnpkg.com/atob/-/atob-2.1.2.tgz#6d9517eb9e030d2436666651e86bd9f6f13533c9"
   integrity sha512-Wm6ukoaOGJi/73p/cl2GvLjTI5JM1k/O14isD73YML8StrH/7/lRFgmg8nICZgD3bZZvjwCGxtMOD3wWNAu8cg==
 
-ava@^1.0.0-beta.8:
+ava@^1.4.1:
   version "1.4.1"
   resolved "https://registry.yarnpkg.com/ava/-/ava-1.4.1.tgz#4a59289e0c9728e492ec3a5be21d1072636be172"
   integrity sha512-wKpgOPTL7hJSBWpfbU4SA8rlsTZrph9g9g7qYDV7M6uK1rKeW8oCUJWRwCd8B24S4N0Y5myf6cTEnA66WIk0sA==
@@ -3622,15 +3622,15 @@ postcss-selector-parser@^6.0.2:
     indexes-of "^1.0.1"
     uniq "^1.0.1"
 
-postcss-value-parser@^3.3.1:
-  version "3.3.1"
-  resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-3.3.1.tgz#9ff822547e2893213cf1c30efa51ac5fd1ba8281"
-  integrity sha512-pISE66AbVkp4fDQ7VHBwRNXzAAKJjw4Vw7nWI/+Q3vuly7SNfgYXvm6i5IgFylHGK5sP/xHAbB7N49OS4gWNyQ==
+postcss-value-parser@^4.0.2:
+  version "4.0.3"
+  resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-4.0.3.tgz#651ff4593aa9eda8d5d0d66593a2417aeaeb325d"
+  integrity sha512-N7h4pG+Nnu5BEIzyeaaIYWs0LI5XC40OrRh5L60z0QjFsqGWcHcbkBvpe1WYpcIS9yQ8sOi/vIPt1ejQCrMVrg==
 
-postcss@^7.0.5:
-  version "7.0.14"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.14.tgz#4527ed6b1ca0d82c53ce5ec1a2041c2346bbd6e5"
-  integrity sha512-NsbD6XUUMZvBxtQAJuWDJeeC4QFsmWsfozWxCJPWf3M55K9iu2iMDaKqyoOdTJ1R4usBXuxlVFAIo8rZPQD4Bg==
+postcss@^7.0.27:
+  version "7.0.27"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.27.tgz#cc67cdc6b0daa375105b7c424a85567345fc54d9"
+  integrity sha512-WuQETPMcW9Uf1/22HWUWP9lgsIC+KEHg2kozMflKjbeUtw9ujvFX6QmIfozaErDkmLWS9WEnEdEe6Uo9/BNTdQ==
   dependencies:
     chalk "^2.4.2"
     source-map "^0.6.1"