Fix release month for 0.12.16 in docs (#7907)
Fix release month for 0.12.16 in docs (#7907)

Does it makes sense to change Apr to May for 0.12.16 release?  Because the final version was released on 14 of May.
ericmjl/bokeh,bokeh/bokeh,mindriot101/bokeh,mindriot101/bokeh,ericmjl/bokeh,ericmjl/bokeh,stonebig/bokeh,jakirkham/bokeh,dennisobrien/bokeh,ericmjl/bokeh,stonebig/bokeh,timsnyder/bokeh,jakirkham/bokeh,dennisobrien/bokeh,stonebig/bokeh,dennisobrien/bokeh,dennisobrien/bokeh,dennisobrien/bokeh,timsnyder/bokeh,bokeh/bokeh,jakirkham/bokeh,jakirkham/bokeh,timsnyder/bokeh,bokeh/bokeh,timsnyder/bokeh,timsnyder/bokeh,mindriot101/bokeh,mindriot101/bokeh,stonebig/bokeh,bokeh/bokeh,jakirkham/bokeh,bokeh/bokeh,ericmjl/bokeh