Fixes validation of AWS::URLSuffix (#174)

* Add AWS::URLSuffix to reference value overrides

This adds the AWS::URLSuffix to the reference value overrides reference
data, as well as to the type used for this value in code.

This is a perfectly valid pseudo parameter (as per
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html#cfn-pseudo-param-urlsuffix)
but was causing an error at
https://github.com/nskoufis/cfn-lint/blob/master/src/validator.ts#L680

* Removing package-lock - not decided upon yet

* Add a test that ensures that the new pseudo param parses correctly

This adds a very simple test that ensures that my minimum working broken
example now passes.

data/aws_ref_override.json

@@ -3,5 +3,6 @@
   "AWS::NotificationARNs": ["arn:aws:sns:us-east-1:123456789012:MyTopic"],
   "AWS::Region": "eu-west-1",
   "AWS::StackId": "AWSREFSTACKID",
-  "AWS::StackName": "AWSREFSTACKNAME"
+  "AWS::StackName": "AWSREFSTACKNAME",
+  "AWS::URLSuffix": "amazonaws.com"
 }

src/awsData.ts

@@ -119,6 +119,7 @@ type RefOverrides = {
     "AWS::Region": string,
     "AWS::StackId": string,
     "AWS::StackName": string,
+    "AWS::URLSuffix": string,
     [refOverride: string]: any
 };
 

src/test/validatorTest.ts

@@ -1022,6 +1022,14 @@ describe('validator', () => {
             expect(result['errors']['crit']).to.have.lengthOf(0);
             expect(result['errors']['warn']).to.have.lengthOf(0);
         });
+
+        it('using the pseudo parameter AWS::URLSuffix should result in validTemplate = true, no crit errors, no warnings', () => {
+            const input = 'testData/valid/yaml/issue-173-url-suffix-pseudo-parameter.yaml';
+            let result = validator.validateFile(input);
+            expect(result).to.have.deep.property('templateValid', true);
+            expect(result['errors']['crit']).to.have.lengthOf(0);
+            expect(result['errors']['warn']).to.have.lengthOf(0);
+        });
     });
 
     describe('custom-resource-attributes', () => {

testData/valid/yaml/issue-173-url-suffix-pseudo-parameter.yaml

@@ -0,0 +1,12 @@
+Resources:
+  TestLambdaPermissionEventsRuleSchedule1:
+    Type: AWS::Lambda::Permission
+    Properties:
+      FunctionName: test
+      Action: lambda:InvokeFunction
+      Principal:
+        Fn::Join:
+          - ''
+          - - events.
+            - Ref: AWS::URLSuffix
+              SourceArn: arn:aws:lambda:us-east-1:123456789012:function:Test