Release v0.3.0

[Sreehari425]

closes #15

This pull request updates the PresenceForge library to version 0.3.0, introducing a breaking change by raising the minimum supported Rust version (MSRV) to 1.81.0. All documentation, configuration, and CI workflows have been updated to reflect the new version and MSRV. This upgrade is required for compatibility with dependencies such as thiserror v2.

Breaking changes and version upgrades:

• Bumped the crate version to 0.3.0 in Cargo.toml, and updated all documentation and usage examples to reference 0.3.0 instead of 0.2.1. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17]

• Increased the minimum supported Rust version to 1.81.0 in Cargo.toml, updated the badge in README.md, and changed the toolchain in rust-toolchain.toml and CI workflow to use Rust 1.81.0. [1] [2] [3] [4]

Documentation and changelog:

• Added a changelog entry for version 0.3.0, detailing the MSRV bump and the rationale (compatibility with thiserror v2).
• Updated all documentation notes and code snippets to reference version 0.3.0 and the new MSRV. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17]

No functional or API changes are introduced in this release, but users must upgrade their Rust toolchain to 1.81.0 or newer to use PresenceForge 0.3.0.