[Fix] import linesearch for modern scipy (#642)

* update import for scalar armijo * add release line in file

Author: rflamary

RELEASES.md

@@ -22,6 +22,7 @@
 - Fix (F)GW barycenter functions to support computing barycenter on 1 input + deprecate structures as lists (PR #628)
 - Fix line-search in partial GW and change default init to the interior of partial transport plans (PR #602)
 - Fix `ot.da.sinkhorn_lpl1_mm` compatibility with JAX (PR #592)
+- Fiw linesearch import error on Scipy 1.14 (PR #642, Issue #641)
 
 ## 0.9.3
 *January 2024*

ot/optim.py

@@ -19,7 +19,7 @@
  try:
  from scipy.optimize import scalar_search_armijo
  except ImportError:
- from scipy.optimize.linesearch import scalar_search_armijo
+ from scipy.optimize._linesearch import scalar_search_armijo
 
 # The corresponding scipy function does not work for matrices