chore(doc): update README with supported versions

Author: shulard

README.md

@@ -30,6 +30,7 @@ used as a single metric defining how good your tests are.
 | 4.x                   | `^7.1`   | `^4.2 \|\| ^5.0 \|\| ^6.0` | `^5.0 \|\| ^6.0 \|\| ^7.0`   |
 | 5.x                   | `>= 7.2` | `^5.0 \|\| ^6.0 \|\| ^7.0` | `^6.0 \|\| ^7.0 \|\| ^8.0`   |
 | 6.x                   | `>= 7.3` | `^6.0 \|\| ^7.0`           | `^9.2 \|\| ^10.0 \|\| ^11.0` |
+| 7.x                   | `>= 8.1` | `^7.0 \|\| ^8.0`           | `^9.2 \|\| ^10.0 \|\| ^11.0` |
 
 ## Change Log