iOS svgChart default fontFamily setting

[iris-j]

I noticed that in v2.0.0, the code converting sans-serif to Helvetica Neue was removed, but in v2.0.2 it was added back.

I remembered that when I used v2.0.0 in November, even if I set the global textStyle in Echarts options, the error "unrecognized fontFamily" still occurred(it seemed like the setting did not apply to all the components of the chart, maybe the tooltip etc. ). Therefore I had to downgrade to v1.x.

It's nice to see that v2.0.2 works again, but I'm curious about the reason behind it. Could you explain?

P.s. Appreciate your contribution. This package really helps me a lot.