Update proxyquire requirement from ^1.7.9 to ^2.1.0

Updates the requirements on [proxyquire](https://github.com/thlorenz/proxyquire) to permit the latest version.
- [Release notes](https://github.com/thlorenz/proxyquire/releases)
- [Commits](https://github.com/thlorenz/proxyquire/commits/v2.1.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

package.json

@@ -50,7 +50,7 @@
     "hexo-renderer-marked": "^0.3.2",
     "istanbul": "^0.4.3",
     "mocha": "^5.2.0",
-    "proxyquire": "^1.7.9",
+    "proxyquire": "^2.1.0",
     "rewire": "^4.0.1",
     "sinon": "^6.3.5"
   },