change to symbol

src/interface.jl

@@ -55,7 +55,7 @@ abstract type agent end
 
   # Ref: Chat prompt format https://huggingface.co/TheBloke/Llama-2-7B-Chat-GGML/discussions/3
   # messages= [Dict(:role=>"system", :content=> "", :timestamp=> Dates.now()),]
-  messages = Vector{Dict{String, Any}}()
+  messages = Vector{Dict{Symbol, Any}}()
   context::String = "nothing" # internal thinking area
   tools::Union{Dict, Nothing} = nothing 
   thought::String = "nothing"  # contain unfinished thoughts