Update deprecated actions & change coverage upload entry

[skyleaworlder]

PR Checklist

• [ ] Tests are added
• [ ] Documentation, if applicable

About FluxML/Flux.jl#1939 & FluxML/Flux.jl#2170

• update actions node 12 => node 16;
• add the same condition of coverage generation like Zygote.jl and Flux.jl.

[yuehhua]

Thank you so much!