diff --git a/tasks/cargo.yml b/tasks/cargo.yml
index bc00d9b..25d51eb 100644
--- a/tasks/cargo.yml
+++ b/tasks/cargo.yml
@@ -3,7 +3,7 @@
 - name: Install cargo {{ pkg }}
   become: "{{ ext_become }}"
   environment:
-    RUSTONIG_SYSTEM_LIBONIG=1
+    RUSTONIG_SYSTEM_LIBONIG: 1
   community.general.cargo:
     name: "{{ pkg.name | default(pkg) }}"
     version: "{{ pkg.vers | default(omit) }}"