benchkit: Fix Node installation in Dockerimage (#1190)

The new node script installer doesn't work with sh, only with bash.

Author: bigmontz

benchkit/Dockerfile

@@ -11,7 +11,7 @@ RUN apt-get update && \
     apt-get upgrade -y && \
     apt-get install -y curl
 
-RUN curl -sL https://deb.nodesource.com/setup_${NODE_VERSION:=10}.x | sh
+RUN curl -sL https://deb.nodesource.com/setup_${NODE_VERSION:=10}.x | bash -
 
 RUN apt-get update && \
     apt-get upgrade -y && \