fix getWorkerID when mac addresses have captalized letters

[moadqassem]

Description

Why is this needed

To solve the worker not found errors, when the mac address of the worker is in upper case.

Fixes: #485

How Has This Been Tested?

How are existing users impacted? What migration steps/scripts do we need?

Checklist:

I have:

• updated the documentation and/or roadmap (if required)
• added unit or e2e tests
• provided instructions on how to upgrade

[codecov]

Codecov Report

Merging #486 (07b5572) into master (4bdd9cb) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #486   +/-   ##
=======================================
  Coverage   32.70%   32.70%           
=======================================
  Files          44       44           
  Lines        3137     3137           
=======================================
  Hits         1026     1026           
  Misses       2019     2019           
  Partials       92       92           

Impacted Files	Coverage Δ
db/workflow.go	30.63% <100.00%> (ø)

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[tstromberg]

This PR looks great - is there any way we could have a unit test added to ensure that we don't break this again in the future?

[moadqassem]

@tstromberg you can extend this case here https://github.com/tinkerbell/tink/blob/master/db/workflow_test.go#L42-L68 and then do a fetch request or workflow get request with a device id that has the characters in lower case.

[gauravgahlot]

Hey @moadqassem, do you mind updating the branch and extend the test as well? It would be great to merge the PR then.

[moadqassem]

@gauravgahlot I have added a test case to cover that d502ede

cc @tstromberg

[gauravgahlot]

Thank you @moadqassem 🚀