Reduce threads to avoid overheating

src/freedombone-ci

@@ -257,8 +257,8 @@ else
         fi
     fi
 fi
-echo $"Compressing image with 3 threads" >> "$build_log_filename"
-if ! xz --no-warn --verbose --keep --threads=3 -3 "${build_directory}"/*.img >> "$build_log_filename"; then
+echo $"Compressing image with 2 threads" >> "$build_log_filename"
+if ! xz --no-warn --verbose --keep --threads=2 -3 "${build_directory}"/*.img >> "$build_log_filename"; then
     exit 40
 fi
 # shellcheck disable=SC2115,SC2086