`-o`/`--remove-if-older-than` broken/wrongly triggers `-r`/`--remove-dir`

```
❯ cargo cache --version                        
cargo-cache 0.8.3
```

```
❯ cargo cache -o 2024.04.01
error: The following required arguments were not provided:
    --remove-dir <dir1,dir2,dir3>
```

```
❯ cargo cache --remove-if-older-than 2024.04.01
error: The following required arguments were not provided:
    --remove-dir <dir1,dir2,dir3>
```
