✨ Add path arg to filter commits

Summary

TL;DR filter commits by path on changelog generation works, but untested.

As discussed in #158, after this comment. One of the tasks to enabling per monorepo package changelogs is to filter commits from a folder.

The dependency responsible for fetching raw commits enables the path option from git log as seen in the docs here

[ ] how to test this behavior with jest?
- I've searched earlier this week how does git stores and tracks the folder structure, but could not understand enough to write a test case to improve code coverage with the new getCommits path option

run
```
node packages/gitmoji-changelog-cli/src/index.js --path packages/gitmoji-changelog-cli
```
- The command is expected to fail with FunctionalError: No changes found. You may need to fetch or pull the last changes.
Add a new comment to the selected testing folder (i.e packages/gitmoji-changelog-cli)
Rerun changelog command with path argument
The result will be something along the lines of
```
<a name="0.0.1"></a>
## 0.0.1 (2022-03-06)
```

🚧 test commit [2640d11]


For reference, without the path argument my changelog for this pr becomes
```md
<a name="0.0.1"></a>
## 0.0.1 (2022-03-06)