feat: support cache-provider

[mindrunner]

This pull request updates the documentation and configuration for a Rust-related GitHub Action, introducing a new cache-provider input and improving formatting consistency in the README.md file. Below are the most important changes grouped by theme:

Documentation Improvements:

• Updated README.md to include the new cache-provider input, explaining its purpose and default value (github).
• Improved formatting consistency in lists and tables within README.md, such as aligning table column headers and using consistent bullet styles. [1] [2] [3]
• Changed italicized text formatting from * to _ for consistency in the README.md.

New Feature:

• Added a cache-provider input to action.yml, allowing users to specify the caching provider (e.g., github or buildjet) with a default value of github.
• Integrated the cache-provider input into the action's runtime configuration under the runs section of action.yml.

[jonasbb]

Thank you for the PR. This looks good :) The cache-provider looks useful to pass through.