Leverage Dependabot for automatic dependencies monitoring

[Toparvion]

As far as AnaLog receives the developers' attention on from-time-to-time basis, it is important to keep an eye on its dependencies set because there can appear stale or even insecure libraries.
For a GitHub hosted project, the easiest way to achieve this seems to leverage Dependabot.
The issue supposes the application of the bot only. Its further customization can be addressed in successive issues as the need arises.