[Backport 2.x] Bump default bwc version to 1.3.4

[opensearch-trigger-bot]

Backport c5b83ed from #477

[codecov-commenter]

Codecov Report

Merging #478 (c5b83ed) into 2.x (bb043e6) will increase coverage by 0.26%.
The diff coverage is 86.05%.

❗ Current head c5b83ed differs from pull request most recent head d332c14. Consider uploading reports for the commit d332c14 to get more accurate results

@@             Coverage Diff              @@
##                2.x     #478      +/-   ##
============================================
+ Coverage     83.82%   84.09%   +0.26%     
- Complexity      933      979      +46     
============================================
  Files           133      140       +7     
  Lines          3828     4031     +203     
  Branches        349      362      +13     
============================================
+ Hits           3209     3390     +181     
- Misses          457      475      +18     
- Partials        162      166       +4     

Impacted Files	Coverage Δ
.../main/java/org/opensearch/knn/index/IndexUtil.java	55.73% <ø> (ø)
...n/java/org/opensearch/knn/index/KNNIndexShard.java	93.75% <ø> (ø)
.../main/java/org/opensearch/knn/index/KNNMethod.java	100.00% <ø> (ø)
...ava/org/opensearch/knn/index/KNNMethodContext.java	92.50% <ø> (ø)
...java/org/opensearch/knn/index/KNNQueryBuilder.java	67.96% <ø> (ø)
...java/org/opensearch/knn/index/MethodComponent.java	88.88% <ø> (ø)
...g/opensearch/knn/index/MethodComponentContext.java	91.13% <ø> (ø)
...java/org/opensearch/knn/indices/ModelMetadata.java	97.08% <ø> (ø)
.../opensearch/knn/plugin/script/KNNScoringSpace.java	91.66% <ø> (ø)
...nsearch/knn/plugin/script/KNNScoringSpaceUtil.java	96.55% <ø> (ø)
... and 33 more

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