[EXT-307] Use SkipInsecureVerify to HTTP call used by runner command

[nramabad]

EXT-307

Checklist

=========

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have checked for similar issues and haven't found anything relevant.
• This is not a security issue (which should be reported here: https://circleci.com/security/)
• I have read Contribution Guidelines.

Changes

• Use SkipInsecureVerify to HTTP call used by runner command to fix bug when CLI is run with insecure / custom certifications

Rationale

We would like users to be able to run the CLI behind proxies and other environments that may be using custom certs

Considerations

I am passing config as a whole since the helper function is now using more than just 2 strings. Unit tests were updated to match new function signature.

Here are some helpful tips you can follow when submitting a pull request:

1. Fork the repository and create your branch from master.
2. Run make build in the repository root.
3. If you've fixed a bug or added code that should be tested, add tests!
4. Ensure the test suite passes (make test).
5. The --debug flag is often helpful for debugging HTTP client requests and responses.
6. Format your code with gofmt.
7. Make sure your code lints (make lint). Note: This requires Docker to run inside a local job.

[codecov]

Codecov Report

Merging #758 (3548f4f) into master (990c791) will increase coverage by 0.01%.
The diff coverage is 85.71%.

❗ Current head 3548f4f differs from pull request most recent head c69fe82. Consider uploading reports for the commit c69fe82 to get more accurate results

@@            Coverage Diff             @@
##           master     #758      +/-   ##
==========================================
+ Coverage   32.63%   32.64%   +0.01%     
==========================================
  Files          46       46              
  Lines        5412     5413       +1     
==========================================
+ Hits         1766     1767       +1     
  Misses       3390     3390              
  Partials      256      256              

Impacted Files	Coverage Δ
cmd/runner/runner.go	56.25% <0.00%> (ø)
api/rest/client.go	70.17% <100.00%> (+0.53%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 990c791...c69fe82. Read the comment docs.