Broken publish step on CI

Summary:
Every `job` is run in a separate container and so, `checkout` step is required for the Git host to be added to `~/.ssh/known_hosts`. Without this step, it will timeout after 10 minutes waiting for you to add (yes) or reject (no) from known hosts (we get this prompt when we checkout from a host for the very first time).
Closes https://github.com/facebook/react-native/pull/17956

Differential Revision: D6968130

Pulled By: hramos

fbshipit-source-id: 6d62166fd375f8f408cf5f18b188f841d035d97f

.circleci/config.yml

@@ -383,9 +383,9 @@ jobs:
   publish_npm_package:
     <<: *android_defaults
     steps:
-      - attach_workspace:
-          at: ~/react-native
-
+      # Checkout code so that we can work with `git` in publish.js
+      - checkout
+      
       # Configure Android SDK and related dependencies
       - run: *configure-android-path
       - run: *install-android-build-dependencies
@@ -597,16 +597,12 @@ workflows:
 
   # Only runs on NN-stable branches
   deploy:
-    jobs:
-      # Checkout repo and run Yarn
-      - checkout_code:
-          filters: *filter-only-stable
-          
+    jobs:          
       # If we are on a stable branch, wait for approval to deploy to npm
       - approve_publish_npm_package:
           filters: *filter-only-stable
           type: approval
+
       - publish_npm_package:
           requires:
-            - checkout_code
             - approve_publish_npm_package