Update dependency typescript to v4 (#40)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

package.json

@@ -57,7 +57,7 @@
     "serve": "^11.3.1",
     "shipjs": "^0.21.0",
     "ts-jest": "^26.0.0",
-    "typescript": "^3.9.5",
+    "typescript": "^4.0.0",
     "typescript-eslint-language-service": "^4.0.0",
     "vue": "^3.0.0-beta.15",
     "vue-i18n": "^9.0.0-alpha.11"

yarn.lock

@@ -7300,10 +7300,10 @@ typescript-eslint-language-service@^4.0.0:
   dependencies:
     read-pkg-up "^7.0.0"
 
-typescript@^3.9.5:
-  version "3.9.5"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.5.tgz#586f0dba300cde8be52dd1ac4f7e1009c1b13f36"
-  integrity sha512-hSAifV3k+i6lEoCJ2k6R2Z/rp/H3+8sdmcn5NrS3/3kE7+RyZXm9aqvxWqjEXHAd8b0pShatpcdMTvEdvAJltQ==
+typescript@^4.0.0:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.2.tgz#7ea7c88777c723c681e33bf7988be5d008d05ac2"
+  integrity sha512-e4ERvRV2wb+rRZ/IQeb3jm2VxBsirQLpQhdxplZ2MEzGvDkkMmPglecnNDfSUBivMjP93vRbngYYDQqQ/78bcQ==
 
 uglify-js@^3.1.4:
   version "3.9.4"