Upgraded sinon to latest (#161)

Author: hiranya911

package-lock.json

@@ -66,7 +66,7 @@
     "@types/nock": "^8.0.33",
     "@types/request": "2.0.6",
     "@types/request-promise": "^4.1.33",
-    "@types/sinon": "^1.16.31",
+    "@types/sinon": "^4.1.2",
     "@types/sinon-chai": "^2.7.27",
     "chai": "^3.5.0",
     "chai-as-promised": "^6.0.0",
@@ -91,7 +91,7 @@
     "request": "^2.75.0",
     "request-promise": "^4.1.1",
     "run-sequence": "^1.1.5",
-    "sinon": "^1.17.3",
+    "sinon": "^4.1.3",
     "sinon-chai": "^2.8.0",
     "ts-node": "^3.3.0",
     "tslint": "^3.5.0",

package.json

@@ -1628,7 +1628,7 @@ describe('FirebaseAuthRequestHandler', () => {
       };
 
       let stub = sinon.stub(HttpRequestHandler.prototype, 'sendRequest')
-        .returns(Promise.reject(mockErrorResponse));
+        .rejects(mockErrorResponse);
       stubs.push(stub);
 
       const requestHandler = new FirebaseAuthRequestHandler(mockApp);
@@ -1647,7 +1647,7 @@ describe('FirebaseAuthRequestHandler', () => {
       };
 
       let stub = sinon.stub(HttpRequestHandler.prototype, 'sendRequest')
-        .returns(Promise.reject(mockErrorResponse));
+        .rejects(mockErrorResponse);
       stubs.push(stub);
 
       const requestHandler = new FirebaseAuthRequestHandler(mockApp);
@@ -1664,7 +1664,7 @@ describe('FirebaseAuthRequestHandler', () => {
       };
 
       let stub = sinon.stub(HttpRequestHandler.prototype, 'sendRequest')
-        .returns(Promise.reject(mockErrorResponse));
+        .rejects(mockErrorResponse);
       stubs.push(stub);
 
       const requestHandler = new FirebaseAuthRequestHandler(mockApp);