feat: add chat completion without streaming

CONTRIBUTING.md

@@ -0,0 +1,55 @@
+# Contribute
+
+- [Getting Started](#getting-started)
+  - [Requirements](#requirements)
+  - [First setup](#first-setup)
+  - [Optional requirements](#optional-requirements)
+  - [Test](#test)
+- [Code of Conduct](#code-of-conduct)
+- [Commit Message Format](#commit-message-format)
+
+---
+
+## Getting Started
+
+### Requirements
+
+- [Rust](https://www.rust-lang.org/tools/install): v1
+
+### First setup
+
+> [!IMPORTANT]  
+> If you're under **Windows**, you nust run all CLI commands under a Linux shell-like terminal (i.e.: WSL or Git Bash).
+
+Then run:
+
+```sh
+git clone https://github.com/ivangabriele/mistralai-client-rs.git # or your fork
+cd ./mistralai-client-rs
+cargo build
+```
+
+### Optional requirements
+
+- [cargo-watch](https://github.com/watchexec/cargo-watch#install) for `make test-*-watch`.
+
+### Test
+
+```sh
+make test
+```
+
+or
+
+```sh
+make test-watch
+```
+
+## Code of Conduct
+
+Help us keep this project open and inclusive. Please read and follow our [Code of Conduct](./CODE_OF_CONDUCT.md).
+
+## Commit Message Format
+
+This repository follow the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) specification and
+specificaly the [Angular Commit Message Guidelines](https://github.com/angular/angular/blob/main/CONTRIBUTING.md#commit).