Add dependabot integration

[S0obi]

Hey @derlin, thanks for this repo!

I feel like the cherry on the cake of this Github Action workflow will be the usage of Dependabot to upgrade project dependencies automatically.

Here is an example I found online for poetry:

version: 2
updates:
  - package-ecosystem: "pip"
    directory: "/"
    schedule:
      interval: "weekly"

Reference : Configuration options for the dependabot.yml file