feat(lib): allow x.y versioning scheme for tools

Previously, Rokit strictly required tool versions to follow the `x.y.z` semantic versioning scheme. This would cause parsing errors when a tool in a manifest or a release on GitHub used a simpler `x.y` version, such as `luau@0.683`. This change introduces support for the `x.y` versioning scheme by transparently converting such versions to a compatible `x.y.0` format before they are processed by the `semver` library. This includes: - A new utility function to convert `x.y` version strings to `x.y.0`, correctly handling pre-release tags and build metadata. - Integration of this utility into the parsing logic for `rokit.toml`, `foreman.toml`, and GitHub release tags. - Enhanced the GitHub release fetching logic to first check for the exact tag (e.g., `v1.2.0`) and then fall back to the `x.y` version (e.g., `v1.2`) if the initial tag is not found. This improves compatibility with repositories that use a two-digit versioning scheme for their releases. Solves #86