[FEATURE] Add a CLI arg to specify path to the config file

[tlegrave]

Is your feature request related to a problem? Please describe.
I'm facing issues where I want to have a global cog.toml config file for several repos to automate a release process (through gitlab CI). However cocogitto actually expects the config file to be placed at the root of the repo and commits it when using cog bump (due to the code here).

Describe the solution you'd like
Allowing cog to take the path to the config file in argument.

Describe alternatives you've considered
I tried different git stuffs to avoid commiting cog.toml file. Adding the entry to a global or local .gitignore is not working as described in this issue.

Am I missing something ? If not, I can surely make a PR by the end of the week to help on that subject.