Get back docker image building for ARM architecture

[acelaya]

Closes #2346

Enable docker image building for ARM architectures

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.77%. Comparing base (e9fe1ac) to head (193be55).
Report is 6 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #2347   +/-   ##
==========================================
  Coverage      93.77%   93.77%           
  Complexity      1702     1702           
==========================================
  Files            276      276           
  Lines           5895     5895           
==========================================
  Hits            5528     5528           
  Misses           367      367           

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[acelaya]

I disabled temporarily the restriction to build docker image during CI only if the Dockerfile changed, and could verify the workaround described in docker/setup-qemu-action#188 (comment) works. See https://github.com/shlinkio/shlink/actions/runs/13029520862/job/36345486359?pr=2347

[theofficialgman]

@acelaya github actions made ARM64 Linux runners free and available for open source repositories recently (2 weeks ago https://github.com/orgs/community/discussions/19197#discussioncomment-11859757). No need to use QEMU if you switch to these native ARM64 runners