Pin SUNDIALS to 7.5 and add migrator to 7.6#8395

Saransh-cpp wants to merge 3 commits intoconda-forge:mainconda-forge/conda-forge-pinning-feedstock:mainfrom

Saransh-cpp:saransh/sundialsSaransh-cpp/conda-forge-pinning-feedstock:saransh/sundialsCopy head branch name to clipboard