chore(docs): update `ADOPTERS.md` to include SAP (#5165)

SAP is an active and collaborating company in the ESO ecosystem.
I have the admission of the company to admit us as Adopter.

Disclaimer: I work at SAP

Signed-off-by: Jakob Möller <jakob.moeller@sap.com>

ADOPTERS.md

@@ -28,6 +28,7 @@
 - [Polarpoint](https://www.polarpoint.io/)
 - [Radio France](https://www.radiofrance.fr/)
 - [Red Hat OpenShift](https://www.redhat.com/en/technologies/cloud-computing/openshift)
+- [SAP](https://www.sap.com/)
 - [Skeeled](https://www.skeeled.com/)
 - [Made People](https://madepeople.se/)
 - [Voiceflow](https://www.voiceflow.com/)