v9.31.0

JumpProcesses v9.31.0

Diff since v9.30.1

Merged pull requests:

• Add a GPU kernel for SSAStepper (#499) (@sivasathyaseeelan)
• Add simple implicit tau-leaping algorithms (#643) (@ChrisRackauckas-Claude)
• Release 9.31.0 (#645) (@ChrisRackauckas)

Closed issues:

• Precompile workload assertion expects 21.0 but evaluates to 28.0 on master (#636)
• Fix failing precompile workload expectation (#640)