Update dependencies + GitLab support

[j-mortara]

Hi @macklinu !

I plan to use your plugin in a project and further extend its capabilities.
As I started updating the codebase, I thought you might be interested in them, although the plugin has not received any update for the past 5 years.

Here are the modifications I brought so far:

• dependencies updates: new versions as well as new packages for deprecated ones;
• a switch from TS to plain JS as it allowed to reduce the codebase and its complexity;
• support for GitLab merge requests.

As these changes quite alter the project, I would understand if you do not wish to merge them.
Yet, I felt like sharing them with you, being the original author of the plugin 🙂

Cheers,

j-mortara