[build] Fix a bash script some times called by sh issue. (sonic-net#1…

…7761)

Why I did it
Fix a bug that sometimes the script runs in sh not bash.

Work item tracking
Microsoft ADO (number only): 26297955
How I did it

scripts/docker_version_control.sh

@@ -1,7 +1,8 @@
+#!/bin/bash
+
 # This script is for reproducible build.
 # Reproducible build for docker enabled: Before build docker image, this script will change image:tag to image:sha256 in DOCKERFILE.
 # And record image sha256 to a target file.
-#!/bin/bash
 
 IMAGENAME=$1
 DOCKERFILE=$2