How to group by values by special characters for unique ids in r

Question

I have a data frame df that looks like below

ID  value
123 6
123 5
123 4
124 3
124 8
137 9
140 12
154 9
154 8
167 10

I need to group them by comma with respective ids and want results like below

ID  value
123 6,5,4
124 3,8
137 9
140 12
154 9,8
167 10

I have tried the below code

library(dplyr)
df %>% group_by(ID) %>% summarise(val=paste(Value, collapse=","))

But results like this with a single row and single column

val
6,5,4,3,8,9,12,9,8,10

kindly help me out

Thanks in advance