Regex is getting cutoff

[spacecowboy]

Hi. Noticed an issue with a regex I'm using.

Example struct:

type Foo struct {
	BusinessRegistrationNumber string `json:"businessRegistrationNumber" jsonschema:"title=Business Registration Number,description=Official business registration number (BRN),minLength=5,maxLength=20,pattern=^[A-Z]{0,2}[0-9A-Z\\-\\.\\/]+$"`
}

Generated schema (Copy pasted and removed unrelated things so might not be right:

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "properties": {
      "businessRegistrationNumber": {
        "type": "string",
        "maxLength": 20,
        "minLength": 5,
        "pattern": "^[A-Z]{0",
        "title": "Business Registration Number",
        "description": "Official business registration number (BRN)"
      },
      "additionalProperties": false,
      "type": "object",
      "description": "The merchants business details"
    }
  },
  "additionalProperties": false,
}

Note the pattern:

        "pattern": "^[A-Z]{0",

which is cuf-off.

[spacecowboy]

pattern=^\\+[1-9][0-9]{1,14}$

also fails to generate properly