ci: Apply dependabot cooldown periods

[achimnol]

What do these changes do?

Apply the default cooldown of one week when running dependabot to reduce possibilities of supply chain attacks.

Are there changes in behavior for the user?

No.

Checklist

• I think the code is well written
• Add a new news fragment into the changes folder

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.57%. Comparing base (ce86470) to head (426ab2e).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #984   +/-   ##
=======================================
  Coverage   81.57%   81.57%           
=======================================
  Files          24       24           
  Lines        1422     1422           
  Branches      190      190           
=======================================
  Hits         1160     1160           
  Misses        186      186           
  Partials       76       76           

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