Release version 0.4.0

Update versions of rand, criterion, and nalgebra

Run formatter and clippy, expand workflow

Improve error reporting and handling

Make workflow actions run examples and on dev branch

Create rust.yml for verification

Fix number of keywords and license in Cargo.toml, fix typos

Merge pull request #11 from AzeezDa/dev

Prepare for 0.3.0 release

Add Monte Carlo (normal and MISER) integrators.

Make internal tests into integration tests.

Restructure global definitions. Add Newton-Cotes.

Update licenses. Add APL2.0 and update years to 2025

Upgrade dependencies: rand to 0.9.1, rand_distr to 0.5.1, and criterion to 0.6.0. Fix the problems the upgrades entailed.

Create FUNDING.yml