ci(renovate): ignore docs deps & update schedule

[Stun3R]

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other changes (could be a refactor, documentation change ect...)

Description

• It updates the schedule to make renovate run every month instead of every weeks
• It adds docs folder to the ignore list

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes (if not applicable, please state why)

[codecov]

Codecov Report

Merging #173 (34c5429) into develop (3e0fa76) will not change coverage.
Report is 31 commits behind head on develop.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #173   +/-   ##
========================================
  Coverage    96.11%   96.11%           
========================================
  Files            3        3           
  Lines          103      103           
  Branches        19       19           
========================================
  Hits            99       99           
  Misses           3        3           
  Partials         1        1