Add new SAP proprietary notice

See https://github.com/SebastianWolf-SAP/cloud-authorization-buildpack/blob/44e6d74bf3d9e40699fb8e9d84ebd54cc5e19d61/.reuse/dep5#L5

> Disclaimer: The code in this project may include calls to APIs (“API Calls”) of
> SAP or third-party products or services developed outside of this project
> (“External Products”).
> “APIs” means application programming interfaces, as well as their respective
> specifications and implementing code that allows software to communicate with
> other software.
> API Calls to External Products are not licensed under the open source license
> that governs this project. The use of such API Calls and related External
> Products are subject to applicable additional agreements with the relevant
> provider of the External Products. In no event shall the open source license
> that governs this project grant any rights in or to any External Products,or
> alter, expand or supersede any terms of the applicable additional agreements.
> If you have a valid license agreement with SAP for the use of a particular SAP
> External Product, then you may make use of any API Calls included in this
> project’s code for that SAP External Product, subject to the terms of such
> license agreement. If you do not have a valid license agreement for the use of
> a particular SAP External Product, then you may only make use of any API Calls
> in this project for that SAP External Product for your internal, non-productive
> and non-commercial test and evaluation of such API Calls. Nothing herein grants
> you any rights to use or access any SAP External Product, or provide any third
> parties the right to use of access any SAP External Product, through API Calls.

This is used in many places https://github.com/search?q="API+Calls+to+External+Products+are+not+licensed+under+the+open+source+license"&type=code

@SebastianWolf-SAP which name should be give to this notice?