Fix yaml lint violation on tkn-bundle task

The task was merged at the same time as the yaml lint checks were
enabled.

Signed-off-by: Luiz Carvalho <lucarval@redhat.com>

task/tkn-bundle/0.1/tkn-bundle.yaml

@@ -100,9 +100,9 @@ spec:
         fi
       done
 
-      if [[ -n "$(params.STEPS_IMAGE)" ]]; then
+      if [[ -n "${STEPS_IMAGE}" ]]; then
         for f in "${FILES[@]}"; do
-          yq e '(.spec.steps[] | select(has("image")).image) = "$(params.STEPS_IMAGE)"' -i $f
+          yq e '(.spec.steps[] | select(has("image")).image) = "env(STEPS_IMAGE)"' -i $f
         done
       fi
 
@@ -115,6 +115,8 @@ spec:
       value: $(params.CONTEXT)
     - name: IMAGE
       value: $(params.IMAGE)
+    - name: STEPS_IMAGE
+      value: $(params.STEPS_IMAGE)
     script: |
       #!/bin/env bash