versions: Update kernel version to 4.19.20

We need to bump the kernel version from 4.14.67 to 4.19.20 in order
to follow the recent kernel config bump.

Fixes kata-containers#1029

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

versions.yaml

@@ -133,7 +133,7 @@ assets:
   kernel:
     description: "Linux kernel optimised for virtual machines"
     url: "https://cdn.kernel.org/pub/linux/kernel/v4.x/"
-    version: "v4.14.67"
+    version: "v4.19.20"
 
 components:
   description: "Core system functionality"