add JDK 23 to build tool table

Author: SethTisue

_overviews/jdk-compatibility/overview.md

@@ -35,6 +35,7 @@ Minimum working versions:
 
 | JDK         | sbt             | mill       |
 |:-----------:|:---------------:|:-----------|
+| 23          | ???             | ???        |
 | 21 (LTS)    | 1.9.0           | 0.11.5     |
 | 17 (LTS)    | 1.6.0           | 0.7.0      |
 | 11 (LTS)    | 1.1.0           | 0.1.5      |