diff --git a/ci/r.yml b/ci/r.yml
index efc6587..f257fbd 100644
--- a/ci/r.yml
+++ b/ci/r.yml
@@ -16,7 +16,7 @@ on:
 
 jobs:
   build:
-    runs-on: macOS-latest
+    runs-on: macos-latest
     strategy:
       matrix:
         r-version: [3.5, 3.6]