Full Changelog: 4.2.0...4.2.1

What's Changed

• Fixing GitHub Actions and adding an environment.yml by @mikaem in #102
• Pypi - use pip instead of conda build by @mikaem in #103

Full Changelog: 4.1.4...4.2.0

• There are now new classes for timestepping based on IMEX Runge Kutta.
• The Rayleigh Benard and Navier Stokes channel flow solvers have been completely rewritten using the new timesteppers
• A solver for micropolar Navier Stokes has been added

• It is now possible to configure how inner products are computed using config['matrix']['assemble']
• All matrix modules for orthogonal polynomials are much improved. Using assemble on subclasses of SpectralMatrix
• Introduced a new way to compute matrices using stencil matrices and the orthogonal basis. This is more efficient in terms of memory than regular Vandermonde type of quadrature.