Incorrect Cobra install command in Cobra documentation

[balagrivine]

Under the install section in Cobra.dev documentation site, the installation command go get -u github.com/spf13/cobra/cobra provided is incorrect.

The current behavior when you try installing cobra using that command is this output. go: module github.com/spf13/cobra@upgrade found (v1.8.1), but does not contain package github.com/spf13/cobra/cobra

The correct installation command should be go get -u github.com/spf13/cobra which installs cobra v1.8.1 successfully