fix: packages/contract-wrappers/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-ANSIREGEX-1583908
- https://snyk.io/vuln/SNYK-JS-SEMVER-3247795

packages/contract-wrappers/package.json

@@ -50,13 +50,13 @@
         "@0x/ts-doc-gen": "^0.0.22",
         "@0x/tslint-config": "^4.1.0",
         "gitpkg": "https://github.com/0xProject/gitpkg.git",
-        "tslint": "5.11.0",
+        "tslint": "5.16.0",
         "typedoc": "^0.15.0",
         "typescript": "3.0.1"
     },
     "dependencies": {
         "@0x/assert": "^3.0.9",
-        "@0x/base-contract": "^6.2.3",
+        "@0x/base-contract": "^7.0.0",
         "@0x/contract-addresses": "^4.11.0",
         "@0x/json-schemas": "^5.1.0",
         "@0x/types": "^3.2.0",