fix!: replace v2 extra with compat-v2

[JP-Ellis]

📝 Summary

Rename the v2 extra/feature to compat-v2. As a result, to install Pact Python with v2 compatibility, you will need to now use:

pip install 'pact-python[compat-v2]`

🚨 Breaking Changes

Installing Pact Python with v2 compatibility requires pip install 'pact-python[compat-v2]', and the old pip install 'pact-python[v2]' is no longer supported.

🔥 Motivation

The v2 group of optional dependencies unfortunately results in an issue when Pact Python is installed using pip, as pip tries to parse the group name as if it were a version. To avoid this, the group has been renamed to compat-v2 which should bypass the version parsing.

While this is a bug in pip, pip comes pre-bundled in many situations and is rarely at the latest version; so it is impractical to wait for the upstream issue to be resolved.

🔨 Test Plan

🔗 Related issues/PRs

Fixes: #1275
Ref: pypa/packaging#938

[Copilot]

Pull Request Overview

This PR renames the v2 optional dependency group to compat-v2 to resolve an issue where pip incorrectly parses the group name as a version specification, causing installation failures.

• Renamed the optional dependency group from v2 to compat-v2 in pyproject.toml
• Updated hatch environment configurations to use the new feature name
• Updated installation documentation to reflect the new naming convention

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pyproject.toml	Updated optional dependency group name and hatch environment configurations
MIGRATION.md	Updated installation instructions to use new compat-v2 feature name

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52%. Comparing base (8223d8b) to head (6951d5b).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

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  Coverage    52%     52%           
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  Files        32      32           
  Lines      3739    3739           
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  Hits       1966    1966           
  Misses     1773    1773           

Flag	Coverage Δ
tests	52% <ø> (ø)

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