Add capability to query deployed commits for a given deployment 📦

[hackebrot]

This PR introduces the ability to retrieve all commits included in a given deployment, addressing a key requirement for accurately measuring Lead Time for Changes in Four Keys.

Key Changes

• Added GitHub REST API integration for comparing commits (with support for paginated responses)
• Rearchitected GitHub code to enable package consumers to select which API to use for higher level operations
• Added higher level function for querying deployed commits for a given deployment
• Introduced structured logging to both the metrics CLI app as well as the github package

Recommended review order

1. go.mod and go.sum for new github.com/google/go-github/v68 dependency
2. Files under pkg/github/rest/ with new GitHub REST API code
3. Files under pkg/github/graphql/ with updated GitHub GraphQL API code
4. Changes for pkg/github/*.go with higher-level GitHub API code
5. Files under pkg/github/internal/test/ with test framework for pkg/github
6. Files under metrics/internal/factory/ for refactored factory code
7. CLI app changes in metrics/cmd/**/*.go
8. Remaining files in metrics/

Issues

Resolve #19
Resolve #30
Resolve #33

Notes

Note: AI tools were used in generating this pull request 🤖