Add dependabot

[wrt54g]

I added dependabot for actions

[claha]

Thanks! Please just fix the yamllint complaint :)

[wrt54g]

@claha How? I don't see any issues in this.

[claha]

@wrt54g Here https://github.com/custom-components/sensor.avanza_stock/runs/7202956724?check_suite_focus=true

yamllint.................................................................Failed

• hook id: yamllint
• exit code: 2 Warning: [document-start] missing document start "---"

[wrt54g]

@claha I did this but I don't think it will work.

[claha]

Looks perfect!