package/openblas: bump to version v0.3.26
For change log since v0.3.25, see:
https://github.com/OpenMathLib/OpenBLAS/releases/tag/v0.3.26
This commit also update _SITE url to follow download url published on
the homepage https://www.openblas.net/
Also https://github.com/xianyi/OpenBLAS is now redirecting to
https://github.com/OpenMathLib/OpenBLAS
Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>