feat: add support for gcp pubsub

[rarguelloF]

Adds support for instrumenting cloud.google.com/go/pubsub

Requires DataDog/dd-trace-go#2852

[eliottness]

LGTM

[RomainMuller]

LGTM

[codecov]

Codecov Report

Attention: Patch coverage is 92.38095% with 8 lines in your changes missing coverage. Please review.

Project coverage is 73.87%. Comparing base (c6451d2) to head (20ac6f0).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
_integration-tests/tests/gcp_pubsub/gcp_pubsub.go	92.38%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #266      +/-   ##
==========================================
+ Coverage   73.48%   73.87%   +0.38%     
==========================================
  Files         144      145       +1     
  Lines        7861     7966     +105     
==========================================
+ Hits         5777     5885     +108     
+ Misses       1655     1653       -2     
+ Partials      429      428       -1     

Components	Coverage Δ
Generators	76.69% <ø> (ø)
Instruments	88.05% <ø> (ø)
Go Driver	72.81% <ø> (ø)
Toolexec Driver	70.88% <ø> (ø)
Aspects	71.95% <ø> (+0.15%)	⬆️
Injector	73.42% <ø> (+0.17%)	⬆️
Job Server	63.76% <ø> (+0.56%)	⬆️
Integration Test Suite	87.84% <92.38%> (+0.20%)	⬆️
Other	73.87% <92.38%> (+0.38%)	⬆️

Files with missing lines	Coverage Δ
_integration-tests/tests/gcp_pubsub/gcp_pubsub.go	92.38% <92.38%> (ø)

... and 4 files with indirect coverage changes