add dependabot to keep github action up-to-date

[nimrof]

This sets up dependabot to check if the actions (like actions/upload-artifact) is up to date,
if it is not it will automatically make pr. once a week.

afik there are now three actions that needs updating so it should make three pr.

It can also be used to keep nugets up-to-date with a little more setup

[trojanobelix]

I have no idea about it, but it looks good :-)

[nimrof]

I have no idea about it, but it looks good :-)

You will find out very soon 🤞

[nimrof]

or not.
@CANopenNode could you enable dependabot?

[CANopenNode]

Dependency graph and Dependabot alerts are now enabled. Something else necessary?

[nimrof]

Nope, maybe we just have to wait?
I have never enable it after i added the config so this is new for me too

And thanks btw :)

[CANopenNode]

Enabled all four options:

• Dependabot alerts
• Dependabot security updates
• Grouped security updates
• Dependabot version updates

Better?

[nimrof]

Works now :), just look at all the pr.
Not sure if it was just a delay or what