Update README

Author: Maik Hummel

README.md

@@ -11,7 +11,7 @@
 
 ### based on Ubuntu 20.04.
 
-> ⚠ This image formerly used the Oracle Java version. But due the license changes since April 2019, it's not longer feasible to rely on. This image is now using OpenJDK 11.
+> ⚠ This image formerly used the Oracle Java version. But due the license changes since April 2019, it's not longer feasible to rely on. This image is now using OpenJDK 8.
 
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