chore: update typescript to version 2.7

package.json

@@ -111,7 +111,7 @@
     "tape-promise": "^2.0.1",
     "ts-node": "^4.0.0",
     "tslint": "^5.4.2",
-    "typescript": "^2.4.1",
+    "typescript": "^2.7.1",
     "write-pkg": "^3.1.0"
   },
   "directories": {

shrinkwrap.yaml

@@ -87,7 +87,7 @@ devDependencies:
   tape-promise: 2.0.1
   ts-node: 4.1.0
   tslint: 5.9.1
-  typescript: 2.6.2
+  typescript: 2.7.1
   write-pkg: 3.1.0
 packages:
   /@commitlint/cli/4.3.0:
@@ -6447,12 +6447,12 @@ packages:
   /typedarray/0.0.6:
     resolution:
       integrity: sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
-  /typescript/2.6.2:
+  /typescript/2.7.1:
     dev: true
     engines:
       node: '>=4.2.0'
     resolution:
-      integrity: sha1-PFtv1/beCRQmkCfwPAlGdY92c6Q=
+      integrity: sha512-bqB1yS6o9TNA9ZC/MJxM0FZzPnZdtHj0xWK/IZ5khzVqdpGul/R/EIiHRgFXlwTD7PSIaYVnGKq1QgMCu2mnqw==
   /typpy/2.0.0:
     dev: false
     resolution:
@@ -7040,7 +7040,7 @@ specifiers:
   tree-kill: ^1.2.0
   ts-node: ^4.0.0
   tslint: ^5.4.2
-  typescript: ^2.4.1
+  typescript: ^2.7.1
   update-notifier: ^2.1.0
   util.promisify: ^1.0.0
   write-json-file: ^2.3.0