Bump rubocop-shopify from 2.0.1 to 2.8.0 (#1769)

* Bump rubocop-shopify from 2.0.1 to 2.8.0

Bumps [rubocop-shopify](https://github.com/Shopify/ruby-style-guide) from 2.0.1 to 2.8.0.
- [Release notes](https://github.com/Shopify/ruby-style-guide/releases)
- [Commits](https://github.com/Shopify/ruby-style-guide/compare/v2.0.1...v2.8.0)

---
updated-dependencies:
- dependency-name: rubocop-shopify
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Create .simplecov

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Jeffrey Warren <jeff@unterbahn.com>

.simplecov

@@ -1,4 +1,4 @@
-SimpleCov.start 'rails' do
+SimpleCov.start('rails') do
   add_group 'Units', 'app/models'
   add_group 'Functionals', 'app/controllers'
   add_group 'Services', 'app/services'

Gemfile.lock

@@ -270,8 +270,8 @@ GEM
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.7.0, < 2.0)
-    rubocop-shopify (2.0.1)
-      rubocop (~> 1.11)
+    rubocop-shopify (2.8.0)
+      rubocop (~> 1.31)
     ruby-hmac (0.4.0)
     ruby-openid (2.9.2)
     ruby-openid-apps-discovery (1.2.0)