docs: Add current version to docs

This helps ensure it is clear, when reading the docs, what version of
mcuboot they correspond with.

Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/docs/contributing.md b/docs/contributing.md
index 5692910..5c601f1 100644
--- a/docs/contributing.md
+++ b/docs/contributing.md
@@ -1,7 +1,7 @@
 # Contributing to the MCUboot project
 
 When contributing to MCUboot, please first discuss the changes you
-wish to make via issue, email or slack.
+wish to make via issue, email or Discord.
 
 ## Pull Request Process
 
diff --git a/docs/index.md b/docs/index.md
index 902a16a..1565434 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -1,6 +1,7 @@
 # MCUboot
 
-MCUboot is a secure bootloader for 32-bits microcontrollers.
+MCUboot is a secure bootloader for 32-bits microcontrollers.  This document is
+for release v2.2.0-rc1.
 
 Please see [Contributing](contributing.md) on how you can contribute to MCUboot.