Convert test coverage report to junit format

[jessicamack]

To track the test results from receptor we need them to be in a JUnit compatible format. This PR adds https://github.com/jstemmer/go-junit-report to convert the test output into an xml report.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.60%. Comparing base (0d71e55) to head (a611ce8).
Report is 1 commits behind head on devel.

@@            Coverage Diff             @@
##            devel    #1148      +/-   ##
==========================================
+ Coverage   42.96%   43.60%   +0.63%     
==========================================
  Files          33       36       +3     
  Lines        6612     7192     +580     
==========================================
+ Hits         2841     3136     +295     
- Misses       3534     3822     +288     
+ Partials      237      234       -3     

see 5 files with indirect coverage changes

Components	Coverage Δ
Go	43.10% <ø> (+0.13%)	⬆️
Receptorctl	49.31% <ø> (∅)

[AaronH88]

Maybe something like this?:

  - name: Install go junit reporting
    run: make go-junit-report

  - name: Run receptor tests
    run: PATH="${PWD}:${PATH}" go test -v 2>&1 ./... | go-junit-report -set-exit-code > report.xml

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud