fix(deps): upgrade simple-git to v4

[mattnewell]

What does this PR do?

Upgrades the plugin's direct simple-git dependency from ^3.36.0 to ^4.0.2.

simple-git 4.0 removed gitP, the default export and simple-git/promise. src/git.ts called simpleGit.gitP(options), so it now uses the named simpleGit export, which is the documented 4.x form. The options passed (baseDir, binary, maxConcurrentProcesses) are unchanged and still valid in 4.x.

Motivation

• simple-git 3.36.0 and its @simple-git/argv-parser 1.1.1 dependency are flagged for CVE-2026-102826, CVE-2026-102827, CVE-2026-102828 and CVE-2026-102829. There is no 3.x release that fixes them; the fixes are in 4.x.

Testing Guidelines

• Build, lint, format check and unit tests pass.
• sls deploy of e2e/fixtures/lambda-node with enableSourceCodeIntegration: true: the function's DD_TAGS had the correct git.commit.sha and git.repository_url.

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog

Depends on DataDog/datadog-ci#2540

🤖 Generated with Claude Code

[tusharf5]

Hi @mattnewell , I submitted a similar PR upgrading simple-git to v4. Feel free to close that one if you're going to merge this one. #739

[mattnewell]

Hi @mattnewell , I submitted a similar PR upgrading simple-git to v4. Feel free to close that one if you're going to merge this one. #739

ha! we were ships crossing in the night. technically yours is better, as you added some tests. but i don't have merge rights, either, so 🤷