Don't lint the eslint-rules directory

[jridgewell]

Also bumps a copyright year. #15204 (comment)

[rsimha]

No trailing commas in .eslintrc.

[rsimha]

Update PR description to reflect this change.

[rsimha]

If that didn't work, just ignore the entire directory in lintGlobs. We can use https://www.npmjs.com/package/eslint-plugin-eslint-plugin to lint the eslint-rules directory.

[rsimha]

Oh, I figured it out. Add .eslintrc to the list of files that don't belong in ruleFiles here, and you should be fine.

amphtml/build-system/eslint-rules/index.js

Lines 22 to 23 in a22e4eb

	const ruleFiles = fs.readdirSync(__dirname).filter(ruleFile =>
	!['index.js', 'node_modules', 'package.json'].includes(ruleFile));

[rsimha]

Turns out a few more changes are needed here. I'm working on a PR.

Edit: Sent out #15426, which closes this PR.