Remove pmd.xml

[chingor13]

We are using google-java-format for code formatting/linting.

Fixes #4751

[codecov]

Codecov Report

Merging #5790 into master will decrease coverage by 1.07%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #5790      +/-   ##
============================================
- Coverage     47.17%    46.1%   -1.08%     
+ Complexity    25130    24189     -941     
============================================
  Files          2389     2456      +67     
  Lines        259836   262158    +2322     
  Branches      29417    29602     +185     
============================================
- Hits         122585   120875    -1710     
- Misses       128321   132172    +3851     
- Partials       8930     9111     +181

Impacted Files	Coverage Δ	Complexity Δ
.../java/com/google/cloud/testing/CommandWrapper.java	90.9% <0%> (-6.07%)	13% <0%> (ø)
...in/java/com/google/cloud/storage/StorageBatch.java	88% <0%> (-4%)	13% <0%> (ø)
...m/google/cloud/vision/v1/ImageAnnotatorClient.java	58.69% <0%> (-3.31%)	15% <0%> (-4%)
...e/cloud/vision/v1p4beta1/ImageAnnotatorClient.java	58.69% <0%> (-3.31%)	15% <0%> (-4%)
...gle/cloud/storage/testing/RemoteStorageHelper.java	61.98% <0%> (-3.06%)	9% <0%> (ø)
...e/cloud/vision/v1p3beta1/ImageAnnotatorClient.java	47.05% <0%> (-2.95%)	9% <0%> (-2%)
...e/cloud/vision/v1p2beta1/ImageAnnotatorClient.java	47.05% <0%> (-2.95%)	9% <0%> (-2%)
.../java/com/google/cloud/speech/v1/SpeechClient.java	48.57% <0%> (-2.78%)	10% <0%> (-2%)
...om/google/cloud/speech/v1p1beta1/SpeechClient.java	48.57% <0%> (-2.78%)	10% <0%> (-2%)
...d/webrisk/v1beta1/WebRiskServiceV1Beta1Client.java	63.41% <0%> (-2.5%)	12% <0%> (-3%)
... and 853 more

---

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 4a95f17...b5f61b9. Read the comment docs.