Don't fail builds on ESLint errors in packages/

Test plan:
  - All existing tests pass

Refs DE-1426

flag=none

Change-Id: Ia809f1cd4f3ee6c8da3d14e266caf340e1ba627a
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/304334
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Cameron Ray <cameron.ray@instructure.com>
QA-Review: Aaron Shafovaloff <ashafovaloff@instructure.com>
Product-Review: Cameron Ray <cameron.ray@instructure.com>

script/eslint

@@ -21,6 +21,7 @@ puts "Linting sub-packages"
 linter_options[:command] = "yarn lint"
 linter_options[:base_dir] = "../../"
 linter_options[:append_files_to_command] = true
+linter_options[:severe_anywhere] = false
 
 package_dirs = `ls -1 packages/*/package.json 2> /dev/null`.split("\n").map { |d| d.sub("/package.json", "") }
 cwd = Dir.pwd