Updated the readme with a little on the tag/release policy

Author: JohnVidler

README.md

@@ -1,4 +1,10 @@
 # codal-microbit-v2
 CODAL target for the micro:bit v2.x series of devices
 
-See https://github.com/lancaster-university/microbit-v2-samples for details on building and using CODAL.
+See https://github.com/lancaster-university/microbit-v2-samples for details on building and using CODAL.
+
+## Tags and Releases
+We tag fairly often, and these may include changes which we are currently testing across the various ecosystems that use CODAL, including Microsoft MakeCode and The Foundation Python editors.
+Consequently, these, while generally more stable than the `feature/` or `tests/` branches are also not _guaranteed_ to be stable and complete.
+
+Releases are selected tags intended to be stable and production-ready; and are the recommended ones to use for anyone implementing or using the CODAL codebase.