Add SAP's Open Source principles to documentation

Added a mention of SAP's Open Source Manifesto and its principles related to Open Source and InnerSource.

Author: spier

patterns/2-structured/document-your-guiding-principles.md

@@ -125,6 +125,7 @@ All Trusted Committers of a project are published.
 * **GitHub**
 * **Robert Bosch GmbH**
 * **Siemens'** InnerSource strategy is built upon the guiding principles of Documentation, Workflow, Transparency, Continuous Integration and Culture which are detailed in their InnerSource portal.
+* **SAP** - The [SAP Open Source Manifesto](https://github.com/SAP/open-source-manifesto) mentions principles that SAP follows that related both to Open Source and InnerSource
 
 ### Europace AG