Version 2.1.9

What's Changed

• update control flow APIs and Docs by @chaoming0625 in #192
• doc: update docs of dynamics simulation by @chaoming0625 in #193
• fix #125: add channel models and two-compartment Pinsky-Rinzel model by @chaoming0625 in #194
• JIT errors do not change Variable values by @chaoming0625 in #195
• fix a bug in math.activations.py by @c-xy17 in #196
• Functionalinaty improvements by @chaoming0625 in #197
• update rate docs by @chaoming0625 in #198
• update brainpy.dyn doc by @chaoming0625 in #199

Full Changelog: V2.1.8...V2.1.9