Upgrade to ESLint v7 (#11857)

* Upgrade to ESLint v7

* Upgrade eslint-plugin-import

* Update peer deps

* Remove max-len from ESLint config

* Update tests

* Only test babel-eslint-* packages in Node >=10

* Remove babel-eslint

* Fix linking in dev

* Add comment to Makefile

* Fix e2e tests

* Add --ignore-engines flag when installing in ESLint packages

* fix: convert tt.questionDot to Punctuator

* chore: update lockfile

Co-authored-by: Huáng Jùnliàng <jlhwung@gmail.com>

scripts/integration-tests/e2e-babel.sh

@@ -21,6 +21,11 @@ cd ../..
 #==============================================================================#
 
 startLocalRegistry "$PWD"/scripts/integration-tests/verdaccio-config.yml
+
+# Install dependencies in individual packages so that we can link them at the top level.
+# todo: remove `-- -- --ignore-engines` in Babel 8
+for package in eslint/*/; do yarn --ignore-engines --cwd $package; done
+
 yarn upgrade --scope @babel
 
 # Test