Update circle.yml to test against typescript@next (palantir#2288)

Author: nchen63

circle.yml

@@ -5,12 +5,12 @@ general:
 dependencies:
   pre:
     - node ./scripts/assertMinCircleNodes.js $CIRCLE_NODE_TOTAL
-    - case $CIRCLE_NODE_INDEX in 0) nvm use 4.1.2 ;; 1) nvm use 5.7 ;; [2-3]) nvm use 6.1 ;; esac
+    - case $CIRCLE_NODE_INDEX in 0) nvm use 4.1.2 ;; 1) nvm use 5.7 ;; [2-4]) nvm use 6.1 ;; esac
   override:
     - yarn
 test:
   override:
-    - case $CIRCLE_NODE_INDEX in [0-2]) yarn verify ;; 3) npm run clean && yarn compile && yarn add [email protected] && yarn test ;; esac:
+    - case $CIRCLE_NODE_INDEX in [0-2]) yarn verify ;; 3) npm run clean && yarn compile && yarn add [email protected] && yarn test ;; 4) npm run clean && yarn compile && yarn add typescript@next && yarn test ;; esac:
         parallel: true
 deployment:
   npm-latest:

scripts/assertMinCircleNodes.js

@@ -1,7 +1,7 @@
-var requiredNodes = 4;
+var requiredNodes = 5;
 var nodes = parseInt(process.argv[2], 10);
 if (requiredNodes != null && requiredNodes > nodes) {
-    console.error("ERROR: You must run CircleCI with 4 parallel nodes");
+    console.error("ERROR: You must run CircleCI with " + requiredNodes + " parallel nodes");
     console.error("    This ensures that different environments are tested for TSLint compatibility");
     console.error("    https://circleci.com/gh/<YOUR ACCOUNT>/tslint/edit#parallel-builds");
     process.exit(1);