Fix multi-arch support and delete docker-build step from CI

[shreyas-badiger]

Following changes included in the PR:

• There is no need to do a local docker-build step as we are already running a make test step.
• Update go version in the Dockerfile to 1.17
• Include additional variables TARGETOS, TARGETARCH
• Include QEMU step in CI

[codecov]

Codecov Report

Merging #356 (224fe67) into master (204f08a) will not change coverage.
The diff coverage is n/a.

❗ Current head 224fe67 differs from pull request most recent head e69db16. Consider uploading reports for the commit e69db16 to get more accurate results

@@           Coverage Diff           @@
##           master     #356   +/-   ##
=======================================
  Coverage   45.17%   45.17%           
=======================================
  Files           7        7           
  Lines         757      757           
=======================================
  Hits          342      342           
  Misses        376      376           
  Partials       39       39           

Flag	Coverage Δ
unittests	45.17% <ø> (ø)

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