jenkins: Downgrade JCasC to work around breaking change

The Jenkins operator groovy scripts are currently broken due to an API change in
JCasC, which prevents all of our configurations from loading. If we downgrade to
a previous point release, everything works.

Change-Id: Ic96c1174b217115a00da5e7ca8384a210a291122
diff --git a/k8s/mendel-linux.yaml b/k8s/mendel-linux.yaml
index 341755e..f958e18 100644
--- a/k8s/mendel-linux.yaml
+++ b/k8s/mendel-linux.yaml
@@ -19,7 +19,7 @@
     - name: job-dsl
       version: "1.77"
     - name: configuration-as-code
-      version: "1.41"
+      version: "1.40"
     - name: configuration-as-code-support
       version: "1.18"
     - name: kubernetes-credentials-provider