[BUG] change strings in output of VaspConvergeWorkChain

[ezpzbz]

Describe the bug

Currently, ENCUT and KSPACING values are reported as string in the output dictionaries. In the case of KSPACING, I multiply them by 1000 within workchain (only for key assignment) to avoid .. This needs to get back to actual values. Current exmaple:

{
    "converged_kspacing": "400",
    "converged_kspacing_conservative": "350",
    "energy_difference": 0.0,
    "final_energy": {
        "200": -53.24188224
    }
}

Steps to reproduce

Running VaspConvergeWorkChain with provided example will reproduce it.

Expected

I need to change this to have the outputs as:

{
    "converged_kspacing": 0.400,
    "converged_kspacing_conservative": 0.350,
    "energy_difference": 0.0,
    "final_energy": {
        0.200: -53.24188224
    }
}