Bump cnab-go to v0.20.0

* jsonschema-lock is finally merged and we can get rid of our fork
* Allow numbers in bundle.json again
* Add support for params of type array
* Add ValidateSchema function
* Add output validation
* Validate parameter defaults
* Validate param regardless of if override or default
* Fix retrieval of outputs when characters in the result id are in the
output name
* Add support for params of object type in ConvertValue (#251)
* Use alternate canonical json library
* Bump docker libraries to newer version

Signed-off-by: Carolyn Van Slyck <[email protected]>

go.mod

@@ -32,7 +32,7 @@ require (
 	github.com/carolynvs/datetime-printer v0.2.0
 	github.com/carolynvs/magex v0.6.0
 	github.com/cbroglie/mustache v1.0.1
-	github.com/cnabio/cnab-go v0.19.0
+	github.com/cnabio/cnab-go v0.20.0
 	github.com/cnabio/cnab-to-oci v0.3.1-beta1
 	github.com/containerd/console v1.0.1
 	github.com/containerd/containerd v1.5.0-beta.1