fn update context failed where context has nested values

[riconnon]

Using a context with hierarchical values (eg. one using the Oracle provider) fn update context will return:

Fn: yaml: unmarshal errors:
  line 5: cannot unmarshal !!map into string

Sample context config:

api-url: https://api.fn.example.com
call-url: https://call.fn.example.com
provider: oracle
oracle:
  profile: oci-profile-name
  compartment-id: ocid1.compartment.oc1..abcdefghijklmnopqrstuvwxyz