Bump the required cider-nrepl version to 0.27

Author: bbatsov

cider.el

@@ -414,7 +414,7 @@ Elements of the list are artifact name and list of exclusions to apply for the a
 (defconst cider-latest-clojure-version "1.10.1"
   "Latest supported version of Clojure.")
 
-(defconst cider-required-middleware-version "0.26.0"
+(defconst cider-required-middleware-version "0.27.0"
   "The CIDER nREPL version that's known to work properly with CIDER.")
 
 (defcustom cider-injected-middleware-version cider-required-middleware-version