mend

Installation step for GHC 8.8.3 added in README and stack.yaml modified to mirror stack-8.8.3.yaml

Author: iamsims

README.md

@@ -59,7 +59,7 @@ stack install
 For GHC 8.6.5:
 
 ```bash
-stack --stack-yaml=stack-8.6.4.yaml install
+stack --stack-yaml=stack-8.6.5.yaml install
 ```
 
 For GHC 8.6.4: