Update README with Job.Snapshot details

[nnellans]

This pull request updates the README.md to improve documentation accuracy, add new features, and update links and examples to reflect the latest GitHub Actions capabilities. The most significant change is the addition of documentation for the new snapshot job keyword and YAML anchors/aliases, as well as updates to links and examples to match the current GitHub Actions documentation and features.

New Features and Documentation:

• Added a section on YAML anchors and aliases, including usage examples and current limitations in GitHub Actions.
• Documented the new snapshot job keyword, explaining its purpose, usage, and syntax for custom runner images. [1] [2]

Documentation Updates and Corrections:

• Updated and expanded documentation links throughout the file to point to the latest and most relevant GitHub Actions documentation pages. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
• Corrected and clarified several examples and descriptions, such as increasing the maximum number of workflow_dispatch inputs from 10 to 25 and updating supported runner types. [1] [2]

Feature and Example Enhancements:

• Added ubuntu-slim as a supported runner type in job examples.
• Updated the nesting limit for reusable workflows from 4 to 10 levels.

Other Updates:

• Bumped the version in the documentation header from 1.0.2 to 1.1.0.
• Added new table of contents entries for the added sections.Added documentation for Job.Snapshot and its usage.