use colorRampPalette instead of limited colorBrewer

This refers to Metrics Reloaded blog post comment by karsten, January 10th, 2017.

plot_versions <- function(start, end, path) {
   known_versions <- c("Other", "0.1.0", "0.1.1", "0.1.2", "0.2.0",
         "0.2.1", "0.2.2", "0.2.3", "0.2.4", "0.2.5", "0.2.6", "0.2.7",
         "0.2.8", "0.2.9")
-  getPalette = colorRampPalette(brewer.pal(12, "Paired"))
+  getPalette = colorRampPalette(c("red", "white", "blue", "yellow", "green", "orange"))
   colours <- data.frame(breaks = known_versions,
-    values = rep(brewer.pal(min(12, length(known_versions)), "Paired"),
-                 len = length(known_versions)),
+    values = getPalette(length(known_versions)),
     stringsAsFactors = FALSE)
   versions <- s[s$version %in% known_versions, ]
   visible_versions <- sort(unique(versions$version))

Could still be tweaked, but works (see atached png)