Convert from odeint to solve_ivp

[alchemyst]

odeint is no longer the recommended integration routine. The v1.2.0 SciPy Docs say

These are the routines developed earlier for scipy. They wrap older solvers implemented in Fortran (mostly ODEPACK). While the interface to them is not particularly convenient and certain features are missing compared to the new API, the solvers themselves are of good quality and work fast as compiled Fortran code. In some cases it might be worth using this old API.