docs: update macOS completion manual for zsh

Author: alexandear

docs/src/docs/welcome/integrations.mdx

@@ -54,7 +54,14 @@ The following plugins support `golangci-lint`:
 
 ### macOS
 
-There are two versions of `bash-completion`, v1 and v2. V1 is for Bash 3.2 (which is the default on macOS), and v2 is for Bash 4.1+. The `golangci-lint` completion script doesn’t work correctly with bash-completion v1 and Bash 3.2. It requires bash-completion v2 and Bash 4.1+. Thus, to be able to correctly use `golangci-lint` completion on macOS, you have to install and use Bash 4.1+ ([instructions](https://itnext.io/upgrading-bash-on-macos-7138bd1066ba)). The following instructions assume that you use Bash 4.1+ (that is, any Bash version of 4.1 or newer).
+#### Zsh
+
+To use `golangci-lint` completion on macOS with `zsh`, which is the default shell since Catalina,
+follow the instructions on `golangci-lint completion zsh --help`.
+
+#### Bash
+
+There are two versions of `bash-completion`, v1 and v2. V1 is for Bash 3.2 and v2 is for Bash 4.1+. The `golangci-lint` completion script doesn’t work correctly with bash-completion v1 and Bash 3.2. It requires bash-completion v2 and Bash 4.1+. Thus, to be able to correctly use `golangci-lint` completion on macOS, you have to install and use Bash 4.1+ ([instructions](https://itnext.io/upgrading-bash-on-macos-7138bd1066ba)). The following instructions assume that you use Bash 4.1+ (that is, any Bash version of 4.1 or newer).
 
 Install `bash-completion v2`: