Update README.md Swift version table (#271)

Update README.md Swift version table

Author: rnro

README.md

@@ -35,7 +35,8 @@ SwiftNIO Extras     | Minimum Swift Version
 `1.14.0 ..< 1.19.0` | 5.5.2
 `1.19.0 ..< 1.20.0` | 5.6
 `1.20.0 ..< 1.23.0` | 5.7.1
-`1.23.0 ...`        | 5.8
+`1.23.0 ..< 1.27.0` | 5.8
+`1.27.0 ...`        | 5.10
 
 On the [`nio-extras-0.1`](https://github.com/apple/swift-nio-extras/tree/nio-extras-0.1) branch, you can find the `swift-nio-extras` version for the SwiftNIO 1 family. It requires Swift 4.1 or better.