Remove refs to RC docs

Author: Tim Bruijnzeels

README.md

@@ -33,14 +33,14 @@ In addition to this we added a small feature, and fixed an interop issue:
 - Listen on IPv4+IPv6 #955
 - Fix rfc6492 interop (AKI format) #948
 
-Upgrade instructions for the RC release are here:
-https://krill.docs.nlnetlabs.nl/en/latest/upgrade.html#v0-12-0
+Upgrade instructions this release are here:
+https://krill.docs.nlnetlabs.nl/en/stable/upgrade.html#v0-12-0
 
 The overview of all issues for this release can be found here:
 https://github.com/NLnetLabs/krill/projects/23
 
-Full documentation for the RC version can be found here:
-https://krill.docs.nlnetlabs.nl/en/latest/
+Full documentation can be found here:
+https://krill.docs.nlnetlabs.nl/
 
 ## 0.11.0 'What about that ROA?'