Drop support for Python 3.8 in GH action conda-packages.yaml workflow

[oleksandr-pavlyk]

Since NumPy 1.25 requires Python version >3.8, and with addition of Python 3.11 in the works, it makes sense for us to stop building for 3.8

[oleksandr-pavlyk]

@antonwolfy @diptorupd for awareness. With the recent addition of 3.11 to the matrix, we end up generating too many binaries. Let me know if this would affect your work.

[diptorupd]

@antonwolfy @diptorupd for awareness. With the recent addition of 3.11 to the matrix, we end up generating too many binaries. Let me know if this would affect your work.

I am fine dropping Python 3.8 support, but let us do it all together otherwise numba-dpex CI for Py 3.8 will start bisbehaving after a while.