Fix true/false values

Change-Id: I724313e9872f380d727d4e47f4d26cb8b44e17c5
diff --git a/playbooks/renovate/dry-run.yaml b/playbooks/renovate/dry-run.yaml
index bfbc527..c43b201 100644
--- a/playbooks/renovate/dry-run.yaml
+++ b/playbooks/renovate/dry-run.yaml
@@ -12,6 +12,6 @@
         GITHUB_COM_TOKEN: fake-token
         RENOVATE_ALLOWED_COMMANDS: '["^curl"]'
         # Dry-run
-        RENOVATE_DRY_RUN: true
+        RENOVATE_DRY_RUN: "true"
         RENOVATE_PLATFORM: local
-        RENOVATE_ONBOARDING: false
+        RENOVATE_ONBOARDING: "false"