v2.9.4

ControlSystemIdentification v2.9.4

Diff since v2.9.3

Merged pull requests:

• add Final Prediction Error (FPE) (#144) (@baggepinnen)
• fix DataInterpolations breaking change (#145) (@baggepinnen)
• CompatHelper: add new compat entry for Statistics at version 1, (keep existing compat) (#146) (@github-actions[bot])
• add better error message for invalid initial guess (#147) (@baggepinnen)