Change Request: Remove `eslintrc` support

[lumirlumir]

As of the upcoming ESLint v10, it appears we will drop support for the eslintrc mode from core.

As part of that process, I'm proposing to remove eslintrc support from the create-config package.

There appears to be eslintrc-related logic throughout the create-config package:

create-config/bin/create-config.js

Line 48 in 61524d1

const type = argv.includes("--eslintrc") ? "eslintrc" : "flat";

create-config/lib/config-generator.js

Line 55 in 61524d1

import { FlatCompat } from "@eslint/eslintrc";

create-config/lib/config-generator.js

Lines 294 to 295 in 61524d1

	// install peer dependencies - it's needed for most eslintrc-style shared configs.
	const peers = await fetchPeerDependencies(config.packageName);

create-config/lib/config-generator.js

Lines 319 to 325 in 61524d1

	} else if (config.type === "eslintrc") {
	needCompatHelper = true;
	const shorthandName = getShorthandName(packageName, "eslint-config");
	exportContent += ` compat.extends("${shorthandName}"),\n`;
	}

create-config/lib/config-generator.js

Line 338 in 61524d1

this.result.devDependencies.push("@eslint/eslintrc", "@eslint/js");

[aladdin-add]

It's no harm to keep it, and I still see its value(even with eslint v10): @eslint/eslintrc is a compatibility toolkit - it allows users to use third-party configs even if they haven't been upgraded to flat config yet.