fix in plots of third notebook

examples/notebooks/3_ABC-SMC_with_ContinuousTimeModel.ipynb

 %% Cell type:markdown id: tags:
 
 # ABC-SMC with ContinuousTimeModel
 
 The package allows the run of ABC-SMC algorithm with models defined by the package.
 
 %% Cell type:code id: tags:
 
 ``` julia
 using MarkovProcesses
 using Distributions
 
 load_model("SIR")
 set_time_bound!(SIR, 100.0)
 parametric_SIR = ParametricModel(SIR, (:ki, Uniform(0.001, 0.0015)))
 
 vec_observations = [simulate(SIR)]
+
 function dist_obs(vec_sim::Vector{Trajectory}, vec_observations::Vector{Trajectory})
     return dist_lp(vec_sim[1], vec_observations[1]; p=2)
 end
 
 epsilon = 0.5 * dist_obs([simulate(SIR)], vec_observations)
 @show epsilon
 
 res_abc = abc_smc(parametric_SIR, vec_observations, dist_obs, nbr_particles = 100, tolerance = epsilon)
 ```
 
 %% Cell type:code id: tags:
 
 ``` julia
 using Plots
-histogram(res_abc.mat_p_end, weights = res_abc.weights_end)
+histogram(vec(res_abc.mat_p_end), weights = res_abc.weights)
+```
+
+%% Cell type:code id: tags:
+
+``` julia
 ```