chore(): Update README

(cherry picked from commit 09f311b)

Author: marcreichel

README.md

@@ -5,6 +5,7 @@ The following matrix shows the Branch to AGP version mapping
 
 | Branch  | AGP                |
 |---------|--------------------|
+| `3.0.x` | 10.0               |
 | `2.0.x` | 10.0               |
 | `1.0.x` | 10.0               |
 | `0.2.x` | 9.0                |