Restoring to MySQL fails when tables include generated columns

Judging from https://dba.stackexchange.com/a/279248, it sounds like

> MariaDB's mysqldump dumps the generated values, but MySQL only accepts DEFAULT as value for a virtual generated column.

Creating the backup works no problem, but I get the following error when running `./backup.sh -r HOST:PORT/DATABASE`:

```
ERROR 3105 (HY000) at line 2517: The value specified for generated column 'foo' in table 'bar' is not allowed.
```

I imagine this issue could be resolved by either:
- Including the workaround using `sed` as described in the stackexchange answer as part of the restore script
- Using an image which executes a non-mariadb version of `mysqldump`

I'll look to add reproduction steps soon!