title: Change line width of leaflet's stroke in leaflet
body: <p>Is it possible, to make the black line thinner?
  Here's a reproducible example, see also <a href="https://stackoverflow.com/a/48863797/5784831">here</a>:</p>
  
  <pre><code>library(leaflet)
  leaflet() %&gt;%
    addTiles() %&gt;%
    addProviderTiles(providers$OpenStreetMap, group = "OSM") %&gt;%
    addProviderTiles(providers$Stamen.TonerLite, group = "Toner Lite") %&gt;%
    addLayersControl(baseGroups = c("OSM", "Toner Lite")) %&gt;% 
    leaflet::addCircleMarkers(lat = 0,
                              lng = 0,
                              color = "black",
                              fillColor = "red",
                              stroke = TRUE,
                              popup = "hello",
                              radius = 10,
                              fillOpacity = 0.7)
  </code></pre>