Fix required Go version

Author: ringods

README.md

@@ -15,7 +15,7 @@ Requirements
 ------------
 
 -	[Terraform](https://www.terraform.io/downloads.html) 0.12.x
--	[Go](https://golang.org/doc/install) >= 1.13 (to build the provider plugin)
+-	[Go](https://golang.org/doc/install) >= 1.14 (to build the provider plugin)
 
 Building The Provider
 ---------------------