Update CLA info in README

Author: d98762625

README.md

@@ -88,9 +88,9 @@ Contributing a new operation to CyberChef is super easy! There is a quickstart s
 
 An installation walkthrough, how-to guides for adding new operations and themes, descriptions of the repository structure, available data types and coding conventions can all be found in the project [wiki pages](https://github.com/gchq/CyberChef/wiki).
 
- - Sign the [GCHQ Contributor Licence Agreement](https://github.com/gchq/Gaffer/wiki/GCHQ-OSS-Contributor-License-Agreement-V1.0)
+ - Sign the [GCHQ Contributor Licence Agreement](https://gist.github.com/p013570/edfbf68fe58d0d057770fde526176558#file-gchq-oss-contributor-license-agreement-md)
  - Push your changes to your fork.
- - Submit a pull request.
+ - Submit a pull request. If you are doing this for the first time, you will be prompted to sign the [GCHQ Contributor Licence Agreement](https://github.com/gchq/Gaffer/wiki/GCHQ-OSS-Contributor-License-Agreement-V1.0) via the CLA assistant on the pull request. This will also ask whether you are happy for GCHQ to contact you about a token of thanks for your contribution, or about job opportunities at GCHQ.
 
 
 ## Licencing