feat: webhook v2 spec upgrade

[vinayteki95]

Description

• V2 adapter is introduced to send v2 spec events
• Source transformer payloads will be built differently for different specs (v1 and v2)
• Features service will be aware of v2 flag from transformer and pick adapter accordingly

Linear Ticket

Resolves INT-2802

Security

• The code changed/added as part of this pull request won't create any security issues with how the software is being used.

[codecov]

Codecov Report

Attention: Patch coverage is 91.30435% with 6 lines in your changes missing coverage. Please review.

Project coverage is 74.76%. Comparing base (ddf04ff) to head (ea8e322).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
services/transformer/features_impl.go	25.00%	2 Missing and 1 partial ⚠️
services/transformer/features.go	0.00%	2 Missing ⚠️
gateway/webhook/webhook.go	90.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5224      +/-   ##
==========================================
- Coverage   74.83%   74.76%   -0.07%     
==========================================
  Files         440      440              
  Lines       61528    61570      +42     
==========================================
- Hits        46044    46033      -11     
- Misses      12958    12998      +40     
- Partials     2526     2539      +13     

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[krishna2020]

features_impl.go returns version based on upgradedToSourceTransformV2 value received by /features response from transformer

when does this come into picture ? and what difference it makes returning v1 vs. v2 here ?

[vinayteki95]

This is used in some test cases as a placeholder for transformer service. This used to return v0 earlier but as v0 is deprecated v1 is the ideal response.
This doesn't affect the actual logic anywhere.

[mihir20]

LGTM