Auto-validation for tracing sample.

[artursouza]

Description

Please explain the changes you've made

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #469

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[codecov]

Codecov Report

Merging #508 (5f379f2) into master (1eff655) will decrease coverage by 0.13%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #508      +/-   ##
============================================
- Coverage     80.43%   80.29%   -0.14%     
+ Complexity      974      973       -1     
============================================
  Files            88       88              
  Lines          3015     3015              
  Branches        330      330              
============================================
- Hits           2425     2421       -4     
- Misses          424      427       +3     
- Partials        166      167       +1     

Impacted Files	Coverage Δ	Complexity Δ
sdk/src/main/java/io/dapr/utils/Retry.java	50.00% <0.00%> (-25.00%)	1.00% <0.00%> (-1.00%)

---

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 1eff655...5f379f2. Read the comment docs.

[wcs1only]

LGTM