test: Bump shellcheck version

test/lint/commit-script-check.sh

@@ -12,7 +12,7 @@
 # one. Any remaining diff signals an error.
 
 export LC_ALL=C
-if test "x$1" = "x"; then
+if test -z $1; then
     echo "Usage: $0 <commit>..."
     exit 1
 fi
@@ -24,7 +24,7 @@ for commit in $(git rev-list --reverse $1); do
     if git rev-list -n 1 --pretty="%s" $commit | grep -q "^scripted-diff:"; then
         git checkout --quiet $commit^ || exit
         SCRIPT="$(git rev-list --format=%b -n1 $commit | sed '/^-BEGIN VERIFY SCRIPT-$/,/^-END VERIFY SCRIPT-$/{//!b};d')"
-        if test "x$SCRIPT" = "x"; then
+        if test -z "$SCRIPT"; then
             echo "Error: missing script for: $commit"
             echo "Failed"
             RET=1