Update README

Author: MFransen69

README

@@ -13,6 +13,10 @@ To build and use the buildroot stuff, do the following:
 4) wait while it compiles
 5) find the kernel, bootloader, root filesystem, etc. in output/images
 
+This repo consist of mutliple branches:
+- main: this branch contains the latest contributions but the hashes for packages will not be updated regularly. 
+Use this branch when you want to work on some of the packages and typically you would use a local override to bump related packes to the latest version (e.g. Thunder and its components)
+
 You do not need to be root to build or run buildroot.  Have fun!
 
 Buildroot comes with a basic configuration for a number of boards. Run