Interface inheritance failure in sol_interface, inconsistent with solc

```rust
sol_interface! {
    interface Parent {
        function test() external pure returns (uint256);
    }
    interface SubA is Parent {
        function test() external pure returns (uint256);
    }
}
```
compile error
```
error: inheritance not supported
  --> src/lib.rs:15:20
   |
15 |     interface SubA is Parent {
   |                    ^^

```