README.md: update Go min required version to 1.16 (ethereum#24713)

Author: koosha--

README.md

@@ -16,7 +16,7 @@ archives are published at https://geth.ethereum.org/downloads/.
 
 For prerequisites and detailed build instructions please read the [Installation Instructions](https://geth.ethereum.org/docs/install-and-build/installing-geth).
 
-Building `geth` requires both a Go (version 1.14 or later) and a C compiler. You can install
+Building `geth` requires both a Go (version 1.16 or later) and a C compiler. You can install
 them using your favourite package manager. Once the dependencies are installed, run
 
 ```shell