(#1462) Bump Mima check to 3.2.6
(#1463) Change verilator version name verilator_4_016 --> v4.016
(#1468) Added Group API Chisel API (bp #1073)
(#1486) Memoize the hashcode of the ChiselCircuitAnnotation
(#1490) Canonicalize construction of Decoupled with no payload
