chore(deps): update dependency typescript to v4 (#144)

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

Author: renovate[bot]

package.json

@@ -137,7 +137,7 @@
     "sourcegraph": "^24.8.0",
     "ts-node": "^8.3.0",
     "tslint": "^5.11.0",
-    "typescript": "^3.9.3",
+    "typescript": "^4.1.2",
     "vscode-languageserver-types": "^3.14.0"
   },
   "dependencies": {

yarn.lock

@@ -6931,10 +6931,10 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-typescript@^3.9.3:
-  version "3.9.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.3.tgz#d3ac8883a97c26139e42df5e93eeece33d610b8a"
-  integrity sha512-D/wqnB2xzNFIcoBG9FG8cXRDjiqSTbG2wd8DMZeQyJlP1vfTkIxH4GKveWaEBYySKIg+USu+E+EDIR47SqnaMQ==
+typescript@^4.1.2:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.1.2.tgz#6369ef22516fe5e10304aae5a5c4862db55380e9"
+  integrity sha512-thGloWsGH3SOxv1SoY7QojKi0tc+8FnOmiarEGMbd/lar7QOEd3hvlx3Fp5y6FlDUGl9L+pd4n2e+oToGMmhRQ==
 
 uglify-js@^3.1.4:
   version "3.10.0"