ci(renovate): disable automatic rebasing

[nightah]

This change is to ensure that our CI workers are not flooded with jobs that fail.
This setting will be removed when the initial backlog has been merged.

[authelia]

Artifacts

These changes are published for testing on Buildkite and DockerHub.

Docker Container

• docker pull authelia/authelia:ci-disable-renovate-rebase

[codecov]

Codecov Report

Merging #1668 (b7fcf33) into master (1448908) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1668      +/-   ##
==========================================
- Coverage   70.19%   70.16%   -0.03%     
==========================================
  Files         149      149              
  Lines        4130     4130              
  Branches      172      172              
==========================================
- Hits         2899     2898       -1     
- Misses       1000     1001       +1     
  Partials      231      231              

Flag	Coverage Δ
backend	71.72% <ø> (ø)
frontend	64.43% <ø> (-0.12%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...iews/LoginPortal/SecondFactor/SecondFactorForm.tsx	57.50% <0.00%> (-2.50%)	⬇️