chore: Upgrade to TS4.

Author: cartant

package.json

@@ -31,7 +31,7 @@
     "rxjs": "^6.0.0",
     "tslint": "^6.0.0",
     "tslint-etc": "^1.5.1",
-    "typescript": "~3.9.2"
+    "typescript": "~4.0.2"
   },
   "homepage": "https://github.com/cartant/rxjs-tslint-rules",
   "husky": {

yarn.lock

@@ -1660,10 +1660,10 @@ type-fest@^0.11.0:
   resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.11.0.tgz#97abf0872310fed88a5c466b25681576145e33f1"
   integrity sha512-OdjXJxnCN1AvyLSzeKIgXTXxV+99ZuXl3Hpo9XpJAv9MBcHrrJOQ5kV7ypXOuQie+AmWG25hLbiKdwYTifzcfQ==
 
-typescript@~3.9.2:
-  version "3.9.7"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.7.tgz#98d600a5ebdc38f40cb277522f12dc800e9e25fa"
-  integrity sha512-BLbiRkiBzAwsjut4x/dsibSTB6yWpwT5qWmC2OfuCg3GgVQCSgMs4vEctYPhsaGtd0AeuuHMkjZ2h2WG8MSzRw==
+typescript@~4.0.2:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.2.tgz#7ea7c88777c723c681e33bf7988be5d008d05ac2"
+  integrity sha512-e4ERvRV2wb+rRZ/IQeb3jm2VxBsirQLpQhdxplZ2MEzGvDkkMmPglecnNDfSUBivMjP93vRbngYYDQqQ/78bcQ==
 
 which-module@^2.0.0:
   version "2.0.0"