chore(package): update sinon to version 9.0.0

Closes #35

Author: greenkeeper[bot]

package.json

@@ -91,7 +91,7 @@
         "publish-please": "^5.4.3",
         "remap-istanbul": "^0.13.0",
         "rimraf": "^2.6.3",
-        "sinon": "^7.2.3",
+        "sinon": "^9.0.0",
         "sinon-chai": "^3.3.0",
         "ts-loader": "^5.3.3",
         "ts-node": "^8.0.2",