[rl-reuse_tool-1] Violation against OSS Rules of Play

[sap-ospo-bot]

A violation against the OSS Rules of Play has been detected.

Rule ID: rl-reuse_tool-1
Explanation: Does README mention REUSE? No

Find more information at: https://sap.github.io/fosstars-rating-core/oss_rules_of_play_rating.html

[MelanieCueppers]

REUSE link has been added to README.md