Revert "Helm step: run source from bash" (#523)

* Revert "Helm step run source from bash (#522)"

This reverts commit 2760ece.

* Update step.yaml

Author: vadim-kharin-codefresh

graduated/helm/step.yaml

@@ -2,7 +2,7 @@ kind: step-type
 version: '1.0'
 metadata:
   name: helm
-  version: 1.1.8
+  version: 1.1.9
   title: Release a Helm chart
   isPublic: true
   description: Update or install a Helm chart.
@@ -214,7 +214,7 @@ spec:
       [[- end -]]
       [[ if .Arguments.commands ]]
       commands:
-        - bash -c 'source /opt/bin/release_chart'
+        - source /opt/bin/release_chart
       [[ range $arg := .Arguments.commands ]]
         - '[[ $arg ]]'
       [[ end ]]