yaml: Remove trust section from examples and tests

With 561ce6f4be ("Remove Notary and Content Trust") we
removed support for content trust. No need to have it
in the YAMLs either.

Signed-off-by: Rolf Neugebauer <rn@rneugeba.io>

test/cases/040_packages/004_dhcpcd/test.yml

@@ -20,8 +20,3 @@ onboot:
 files:
   - path: check.sh
     source: ./check.sh
-trust:
-  org:
-    - linuxkit
-  image:
-    - alpine:3.11