Update go version requirement to 1.21.x in docs

Author: asmarton

docs/installation.md

@@ -457,7 +457,7 @@ This will mainly affect Debian, Ubuntu, and related distributions, or RHEL where
 
 #### golang
 
-Be careful to double-check that the version of golang is new enough (i.e. `go version`), as of January 2022 version is 1.16.x or higher is required.
+Be careful to double-check that the version of golang is new enough (i.e. `go version`), as of May 2024 version is 1.21.x or higher is required.
 The current minimum required version can always be found in the [go.mod](https://github.com/containers/podman/blob/main/go.mod) file.
 If needed, golang kits are available at https://golang.org/dl/. Alternatively, go can be built from source as follows
 (it's helpful to leave the system-go installed, to avoid having to [bootstrap go](https://golang.org/doc/install/source):
@@ -522,7 +522,7 @@ apt-get install -y \
 
 ### Get Source Code
 
-First, ensure that the `go version` that is found first on the $PATH is 1.16.x or higher. Instruction [above](#golang) will help you compile newer version of Go if needed. Then we can build Podman:
+First, ensure that the `go version` that is found first on the $PATH is 1.21.x or higher. Instruction [above](#golang) will help you compile newer version of Go if needed. Then we can build Podman:
 
 ```bash
 git clone https://github.com/containers/podman/