Adjust the position of each text to the top center of its grouped vertical bar plot columns in ggplo-CodePudding

By the code below, I generate a grouped bar plot below:

df <- data.frame(Person = c("Mr.A","Mr.B"), Cats = c(3,4), Dogs = c(1,2))
data.m <- melt(df, id.vars='Person')

ggplot(data.m, aes(Person, value))   
  geom_bar(aes(fill = variable), width = 0.4, position = position_dodge(width=0.5), stat="identity")  
  geom_text(
    aes(x = Person, y = value, label=value), 
    position = position_dodge(width=1),
    # position = 'dodge', 
    # hjust=-1, 
    vjust=-0.25)  
  theme(legend.position="top", 
        legend.title = element_blank(),
        axis.title.x=element_blank(), 
        axis.title.y=element_blank())

Now my question is how could we adjust the text in the middle of each bar column (as the arrows shown in the figure above), I tried by paramters: position=position_dodge(width=1), position='dodge', hjust=-1 and hjust=1, it seems not working. Someone could help? Thanks.

Reference: