Add `instance IsString (Prop RowKey)`.
Add `instance IsString (Prop RowKey)`.

So we can write:

```
-Inj (RowExists "accounts" (PLit "bob")) <=> Success'
+Inj (RowExists "accounts" "bob") <=> Success'
```

kadena-io/pact,kadena-io/pact,kadena-io/pact,kadena-io/pact