[ci] Upgrade github action gradle plugin to v3

[frankfliu]

Description

Brief description of what this PR is about

• If this change is a backward incompatible change, why must this change be made?
• Interesting edge cases to note here

[codecov-commenter]

Codecov Report

Patch coverage: 71.62% and project coverage change: +1.59 🎉

Comparison is base (bb5073f) 72.08% compared to head (d077b26) 73.68%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2576      +/-   ##
============================================
+ Coverage     72.08%   73.68%   +1.59%     
- Complexity     5126     6959    +1833     
============================================
  Files           473      684     +211     
  Lines         21970    30363    +8393     
  Branches       2351     3152     +801     
============================================
+ Hits          15838    22374    +6536     
- Misses         4925     6455    +1530     
- Partials       1207     1534     +327     

Impacted Files	Coverage Δ
api/src/main/java/ai/djl/modality/cv/Image.java	69.23% <ø> (-4.11%)	⬇️
...rc/main/java/ai/djl/modality/cv/MultiBoxPrior.java	76.00% <ø> (ø)
.../main/java/ai/djl/modality/cv/output/Landmark.java	100.00% <ø> (ø)
...i/djl/modality/cv/translator/BigGANTranslator.java	21.42% <0.00%> (-5.24%)	⬇️
.../modality/cv/translator/ImageFeatureExtractor.java	0.00% <0.00%> (ø)
.../ai/djl/modality/cv/translator/YoloTranslator.java	27.77% <0.00%> (+18.95%)	⬆️
...ain/java/ai/djl/modality/cv/util/NDImageUtils.java	67.10% <0.00%> (+7.89%)	⬆️
api/src/main/java/ai/djl/modality/nlp/Decoder.java	63.63% <ø> (ø)
api/src/main/java/ai/djl/modality/nlp/Encoder.java	66.66% <ø> (ø)
.../main/java/ai/djl/modality/nlp/EncoderDecoder.java	64.00% <ø> (ø)
... and 228 more

... and 352 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.