(math/R-estimability) Updated 1.4.1 to 1.5,  make test passed

** NOTE: If you have v1.4 installed, please update to a newer version!
**      (Or an older one, for that matter)

1.5
    We now require R >= 4.3.0.
    Plays along with the changes in 'predict.lm' that came with R 4.3.0.
    We re-coded the 'nonest.basis.qr' to something much simpler, and the
    old version is kept available as 'legacy.nonest.basis'.
    And a vignette was added to help developers add estimability
    checking to their package.

(mef)