Do not show messages in episode 9

episodes/09-open-and-plot-vector-layers.Rmd

@@ -40,7 +40,7 @@ In this lesson you will work with the `sf` package. Note that the `sf` package h
 
 First we need to load the packages we will use in this lesson. We will use the `tidyverse` package with which you are already familiar from the previous lesson. In addition, we need to load the [`sf`](https://r-spatial.github.io/sf/) package for working with spatial vector data. 
 
-```{r lib, message=FALSE}
+```{r lib, warning=FALSE, message=FALSE}
 library(tidyverse)  # wrangle, reshape and visualize data
 library(sf)         # work with spatial vector data
 ```