Add Spec file/versioning information to the Issue Template (aws-cloud…

…formation#679)

.github/ISSUE_TEMPLATE.md

@@ -6,5 +6,9 @@ Please provide as much information as possible:
 * Template linting issues:
   * Please provide a CloudFormation sample that generated the issue.
   * If present, please add links to the (official) documentation for clarification.
+  * Validate if the issue still exists with the latest version of `cfn-lint` and/or the latest Spec files
 * Feature request:
   * Please provide argumentation about the missing feature. Context is key!
+
+
+Cfn-lint uses the [CloudFormation Resource Specifications](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-resource-specification.html) as the base to do validation. These files are included as part of the application version. Please update to the latest version of `cfn-lint` or update the spec files manually (`cfn-lint -u`)