fix: Change secret key reference to use 'value' instead of 'key'

Signed-off-by: just1900 <legendj228@gmail.com>

Author: just1900

charts/velero/templates/deployment.yaml

@@ -260,7 +260,7 @@ spec:
               valueFrom:
                 secretKeyRef:
                   name: {{ include "velero.secretName" $ }}
-                  key: {{ default "none" $key }}
+                  key: {{ default "none" $value }}
           {{- end }}
           {{- end }}
           {{- if .Values.lifecycle }}