refactor: fix quotes for dry_run

Author: jsjoeio

ci/build/release-prep.sh

@@ -12,12 +12,7 @@ set -euo pipefail
 main() {
   if [ "${DRY_RUN-}" = 1 ]; then
     echo "Performing a dry run..."
-    # Disabled because shellcheck wants me to do this
-    # SC2209: Use var=$(command) to assign output (or quote to assign string).
-    # But neither of those match my needs
-    # We do this so that the dry run echos the commands instead of running them
-    # shellcheck disable=SC2209
-    CMD=echo
+    CMD="echo"
   else
     CMD=''
   fi