refactor!: drop support for lerna v2

BREAKING CHANGE: remove lerna v2 support and tests

@commitlint/config-lerna-scopes/index.test.js

@@ -1,6 +1,5 @@
 import {lerna} from '@commitlint/test';
 import config from '.';
-import semver from 'semver';
 
 test('exports rules key', () => {
 	expect(config).toHaveProperty('rules');
@@ -67,31 +66,3 @@ test('returns expected value for scoped lerna repository', async () => {
 	const [, , value] = await fn({cwd});
 	expect(value).toEqual(['a', 'b']);
 });
-
-test('works with lerna version < 3', async () => {
-	const {'scope-enum': fn} = config.rules;
-	const cwd = await lerna.bootstrap('lerna-two', __dirname);
-	const [, , value] = await fn({cwd});
-	expect(value).toEqual(['a2', 'b2']);
-});
-
-test('uses lerna version < 3 if installed', async () => {
-	const semverLt = jest.spyOn(semver, 'lt');
-	const cwd = await lerna.bootstrap('lerna-two', __dirname);
-	const packages = await config.utils.getPackages({cwd});
-
-	expect(packages).toEqual(['a2', 'b2']);
-	expect(semverLt).toHaveBeenLastCalledWith('2.11.0', '3.0.0');
-	expect(semverLt).toHaveLastReturnedWith(true);
-});
-
-test('uses lerna version >= 3 if installed', async () => {
-	const semverLt = jest.spyOn(semver, 'lt');
-	const cwd = await lerna.bootstrap('basic', __dirname);
-
-	const packages = await config.utils.getPackages({cwd});
-
-	expect(packages).toEqual(['a', 'b']);
-	expect(semverLt).toHaveBeenLastCalledWith('3.20.2', '3.0.0');
-	expect(semverLt).toHaveLastReturnedWith(false);
-});

@commitlint/config-lerna-scopes/package.json

@@ -26,7 +26,7 @@
   },
   "homepage": "https://github.com/conventional-changelog/commitlint#readme",
   "peerDependencies": {
-    "lerna": "^2.11.0 ^2.11.0"
+    "lerna": "^3.22.1"
   },
   "engines": {
     "node": ">=v10.22.0"

@packages/test/src/lerna.ts

@@ -3,14 +3,18 @@ import fs from 'fs-extra';
 import resolvePkg from 'resolve-pkg';
 import * as fix from './fix';
 
-export type LernaFixture = 'basic' | 'empty' | 'lerna-two' | 'scoped';
+export type LernaFixture = 'basic' | 'empty' | 'scoped';
 
 export async function bootstrap(
 	fixture: string,
 	directory: string
 ): Promise<string> {
 	const cwd = await fix.bootstrap(`fixtures/${fixture}`, directory);
-	const lerna = fixture === 'lerna-two' ? 'lerna-v2' : 'lerna-v3';
+	// this used to test lerna v2 and v3
+	// the v2 option is removed here, lerna version tests as well
+	// all the code to test differnt version is still in place
+	// cause i'm not sure how to remove this properly
+	const lerna = 'lerna-v3';
 	await fs.mkdirp(path.join(cwd, 'node_modules', '@lerna'));
 	await fs.symlink(
 		resolvePkg('@lerna/project')!,

package.json

@@ -90,7 +90,6 @@
     "husky": "4.2.5",
     "jest": "25.1.0",
     "lerna": "^3.22.1",
-    "lerna-v2": "npm:lerna@2",
     "lerna-v3": "npm:lerna@3",
     "lint-staged": "10.3.0",
     "prettier": "^2.0.5",