Updates to sciml model test cases for PEtav v2

[BSnelling]

• estimate in the parameters table updated to be true | false: https://petab.readthedocs.io/en/latest/v2/documentation_data_format.html#parameter-table
• version and required added to problem.yaml under extensions.sciml, these are required properties according to the yaml schema: https://petab.readthedocs.io/en/latest/v2/documentation_data_format.html#yaml-file-for-grouping-files
• format_version changed to a string
  • this may be a bugto report elsewhere?
  • the schema says an integer should be fine here but the python importer fails if it is not a string and the petab test suite uses version number strings

[BSnelling]

Does the petab_sciml format specification have a version yet?

[sebapersson]

No, 0.1.0 will be the first version, but lets wait with that feature until we actually release 0.1

[sebapersson]

Thanks a lot for spotting this! I will check nothing broke with PEtab.jl, then I will merge!

[sebapersson]

Everything works as expected in PEtab.jl, so I will merge.

Thanks again!