The rule @typescript-eslint/interface-name-prefix has been removed as you can see here.
You can achieve the same effect of [ "error", { "prefixWithI": "always" }] with the following:
{
"@typescript-eslint/naming-convention": [
"error",
{
"selector": "interface",
"format": ["PascalCase"],
"custom": {
"regex": "^I[A-Z]",
"match": true
}
}
]
}