Fix call to round for Julia 1.0 (#28944)

(cherry picked from commit 2346be8)

Author: iht

doc/src/manual/parallel-computing.md

@@ -1086,7 +1086,7 @@ julia> for p in workers() # start tasks on the workers to process requests in pa
 
 julia> @elapsed while n > 0 # print out results
            job_id, exec_time, where = take!(results)
-           println("$job_id finished in $(round(exec_time,2)) seconds on worker $where")
+           println("$job_id finished in $(round(exec_time; digits=2)) seconds on worker $where")
            n = n - 1
        end
 1 finished in 0.18 seconds on worker 4