Automatically run `solc-select upgrade` on pip3 upgrades

To get the most up-to-date solc-select version, users have to run `pip install solc-select --upgrade`.

With the recent changes in refactoring, if solc-select detects the old architecture, it will print an error message and ask a user to run `solc-select upgrade`. As a result, users need to run these two commands to update solc-select, which is clunky:

```bash
pip install solc-select --upgrade
solc-select upgrade
```
Before releasing the refactor and Windows support, find a way to automatically run the `solc-select upgrade` command on installations so users only need to run the first pip command.