CVSS storing problem

We store a CVSS Vectors in the `value` field in our old model but the maximum length is `50` chars,
so I think we need to make sure our new field big enough .
```
>>> len('AV:L/AC:L/Au:M/C:N/I:P/A:C/E:U/RL:W/RC:ND/CDP:L/TD:H/CR:ND/IR:ND/AR:M')
69
>>> len("CVSS:3.0/S:C/C:H/I:H/A:N/AV:P/AC:H/PR:H/UI:R/E:H/RL:O/RC:R/CR:H/IR:X/AR:X/MAC:H/MPR:X/MUI:X/MC:L/MA:X")
101
>>> len("AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/CR:X/IR:X/AR:X/MAV:N/MAC:X/MPR:N/MUI:R/MS:U/MC:H/MI:N/MA:N")
94
```
https://advisories.stormshield.eu/2021-025/