fix: use compile_native_go_fuzzer_v2 compiler for OSS-Fuzz build.

[sudiptob2]

Many Go projects, including Envoy Gateway, had been facing issues with coverage builds in OSS-Fuzz.
To address this, OSS-Fuzz has introduced compile_native_go_fuzzer_v2.

This PR updates our fuzzing build script to use the new compile_native_go_fuzzer_v2.

Ref: google/oss-fuzz#13835

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.91%. Comparing base (fa9f9c3) to head (7e3467d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7296      +/-   ##
==========================================
- Coverage   70.92%   70.91%   -0.02%     
==========================================
  Files         229      229              
  Lines       41071    41071              
==========================================
- Hits        29131    29124       -7     
- Misses      10221    10226       +5     
- Partials     1719     1721       +2     

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