Refactor dependabot.yml to use single directory entries for docker

[anrossi]

Description

Updated dependabot configuration to use single directory entries for Ubuntu Docker images.

Testing

Running the dependabot tool

Documentation

N/A

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.71%. Comparing base (6c0fd3a) to head (ed6c028).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5625      +/-   ##
==========================================
- Coverage   85.62%   84.71%   -0.92%     
==========================================
  Files          60       60              
  Lines       18663    18663              
==========================================
- Hits        15980    15810     -170     
- Misses       2683     2853     +170     

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