v0.3.0

This PR adds all of the main functionality to the staking contract

New Features

• Added staking endpoint
• Added endpoint to know the amount staked
• Added endpoint to know current reward
• Added endpoint to know total reward
• Added endpoint to withdraw token and reward
• Added tests
• Added CI

Fixed

Naming conventions
Linting duplicate std issue

What else Changed

• Latest state by @tyshkor in #4
• Current state by @tyshkor in #3

New Contributors

• @tyshkor made their first contribution in #4

Full Changelog: v0.2.61...v0.3.0