* runtime cpu dispatch

* force thread one

* disable openmp for coverage

* simplify test layer

* print NCNN_TARGET_ARCH

* less ci build variants

* weight fp16 storage option

* test convdw int8

* apple a12 a13

* ncnn_add_layer ncnn_add_shader cmake macro

* try checkout v2 to resolve some ci issue

* delete ccpp.yml

* add build.yml

* split all workflows

* delete single file defined workflows

* light up the building status matrix

* use short icons

* add actions to ios 32bit cpu position

* rename ios workflow file's name

* rename ios workflow name