Make target file relative to script file

Since we expect them to be in the same directory

verify-script.template

@@ -17,9 +17,10 @@
 
 MESSAGE="{message}"
 FILE="{filename}"
+FILE_PATH="$(dirname "$0")/$FILE"
 EXPECTED_HASH="{filehash}"
 
-if [ "$(sha256sum "$FILE" | awk '{print $1}')" = "$EXPECTED_HASH" ]; then
+if [ "$(sha256sum "$FILE_PATH" | awk '{print $1}')" = "$EXPECTED_HASH" ]; then
 	printf "File %s validated with message:\\n%s" "$FILE" "$MESSAGE"
 	exit 0
 else