feat: custom reference prefix

[KeidsID]

Related to issue #17, the current version of this library only accepts "#" as the reference prefix.

The commitlint.js had a configuration to modify this.

import { RuleConfigSeverity, UserConfig } from "@commitlint/types";

const config: UserConfig = {
  extends: ["@commitlint/config-conventional"],
  parserPreset: {
    parserOpts: {
      issuePrefixes: "sv-", // `<type>: <msg> sv-<issue-num>` pattern
    },
  },
};

export default config;

I would love to have this feature on my dart projects ❤️