[PROPOSAL] add a path for the repository

[EricSimon]

The report is generated at the root workspace, insome context i need to change the outpur$t path and the file name
Indeed (because I m a maven man) all build information is write in * target * directory and this directory is in my * .gitignore *
Example :

> cat masked.jsonl | mimo --output target/ real.jsonl

> cat masked.jsonl | mimo -o target/ real.jsonl 

> cat masked.jsonl | mimo --output myHTML.html real.jsonl

> cat masked.jsonl | mimo -o target/myHTML.html real.jsonl 

The final * / * should define the stringis a directory (and create this path if not exist)