Adapt PR-Template to match other SDKs

Author: Lorenz Nickel

.github/PULL_REQUEST_TEMPLATE.md

@@ -34,7 +34,7 @@
 <!--- The SDK is released under the [Apache 2.0 license][license], so any code you submit will be released under that license -->
 <!--- For substantial contributions, we may ask you to sign a [Contributor License Agreement (CLA)][cla] -->
 <!--- Put an `x` in the below box if you confirm that this request can be released under the Apache 2 license -->
-- [ ] By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
+- [ ] I confirm that this pull request can be released under the Apache 2 license
 
 [issues]: https://github.com/alexa/alexa-skills-kit-sdk-for-python/issues
 [license]: http://aws.amazon.com/apache2.0/