Increase max config store value length

The maximum allowed length for a config store entry's value is now
configurable. The default is still 8k characters, but may be larger.
This increases the limit in the CLI to 64k. If a user attempts to create
an entry larger than their allowed limit, the API will return an error.

Author: awilliams-fastly

pkg/commands/configstoreentry/errors.go

@@ -9,7 +9,7 @@ import (
 
 const (
 	maxKeyLen   = 256
-	maxValueLen = 8000
+	maxValueLen = 2 << 15
 )
 
 var errNoSTDINData = fsterr.RemediationError{