Added some notes about endless labels to readme

set version to 0.4.0 in changelog

CHANGELOG.md

@@ -1,4 +1,4 @@
-# next
+# 0.4.0
 
 - Added support for printing endless labels
 

README.md

@@ -42,6 +42,11 @@ The label size and printer are configured via environmental variables. You can a
 
 Included fonts are `NotoSans-Regular.ttf` and `NotoSerif-Regular.ttf`
 
+## Endless Labels
+
+These are supported, for example the `62` label size. The length of the label will be big enough to accommodate the max number of lines including a margin.
+You may want to experiment with font sizes and line count to get the most out of it.
+
 ## Endpoints
 
 Two endpoints are available `/print` and `/image` both accept the same parameters. `/image` will return the rendered image as a PNG instead of sending to the printer.
@@ -101,4 +106,4 @@ An example `docker-compose.yml` file can be found [here](docker-compose.yml).
 
 I'll try to keep on top of bugs but feature requests may go unfulfilled. Please use the issue tracking in Github.
 
-PRs are welcome!
+PRs are welcome!