♻️💄 simplify KorAPConnection class instantiations to modern syntax

Update all class instantiations from `new("KorAPConnection")` to `KorAPConnection()`.
This is possible with R >= 4.0.

Change-Id: I01131fb32045e084cafbb9e05cd8ba99f8f20f1b
diff --git a/demo/relativeTextpositionBoxplot.R b/demo/relativeTextpositionBoxplot.R
index 02823da..6bb71a1 100644
--- a/demo/relativeTextpositionBoxplot.R
+++ b/demo/relativeTextpositionBoxplot.R
@@ -2,7 +2,7 @@
 library(highcharter)
 library(tidyverse)
 
-kco <- new("KorAPConnection", verbose = TRUE)
+kco <- KorAPConnection(verbose = TRUE)
 
 set.seed(7)