chore(circle): Update crystal version

DanSnow · DanSnow · commit 80fbf43dfa66 · 2017-02-22T10:22:39.000+08:00
diff --git a/circle.yml b/circle.yml
@@ -1,6 +1,6 @@
 machine:
   environment:
-    CRYSTAL_VERSION: "0.20.5"
+    CRYSTAL_VERSION: "0.21.0"
     PATH: "${PATH}:${HOME}/.crystal/bin"
     CRYSTAL_URL: "https://github.com/crystal-lang/crystal/releases/download/${CRYSTAL_VERSION}/crystal-${CRYSTAL_VERSION}-1-linux-x86_64.tar.gz"
 dependencies:
