Chore: update circle.yml

Author: mysticatea

circle.yml

@@ -1,16 +1,16 @@
 machine:
   node:
-    version: 8
+    version: 10
 
 dependencies:
   pre:
     - nvm install 6
-    - nvm install 4
+    - nvm install 8
 
 test:
   override:
-    - nvm use 4 && npm test
     - nvm use 6 && npm test
     - nvm use 8 && npm test
+    - nvm use 10 && npm test
     # Test for the minimum version we are supporting.
-    - nvm use 8 && npm i eslint@3.18.0 --no-save && $(npm bin)/mocha tests/lib/rules/*.js --reporter dot
+    - nvm use 10 && npm i eslint@5.0.0 --no-save && $(npm bin)/mocha tests/lib/rules/*.js --reporter dot