Ritest: use joblib to parallelize iterations for randomization-t

[s3alfisc]

We have recently added joblib as a dependency to parallelize bootstrap inference in the decompose() class.

We should make use of it in the ritest method as well, when we loop over pf.feols() when computing randomization inference via the "randomization-t" algo.

In a nutshell, we want to parallelize this for loop with joblib:

pyfixest/pyfixest/estimation/ritest.py

Line 83 in 611e5cc

for i in tqdm(range(reps)):

[s3alfisc]

Would this be of interest to either one of you @marcandre259 or @IshwaraHegde97?

[IshwaraHegde97]

Happy to have a go at this!