Wrong version in the README example when install specific version

[lbellomo]

In the readme there is a error when installing a specific version: it shows the same version as in the common installation above instead of showing the one passed as environment variable.

mise/README.md

Lines 36 to 48 in f71e3ef

	```sh-session
	$ curl https://mise.run | sh
	$ ~/.local/bin/mise --version
	mise 2024.8.12
	```
	or install a specific a version:
	```sh-session
	$ curl https://mise.run | MISE_VERSION=v2024.5.16 sh
	$ ~/.local/bin/mise --version
	mise 2024.8.12
	```

The last one should be

[...]
$ curl https://mise.run | MISE_VERSION=v2024.5.16 sh 
$ ~/.local/bin/mise --version 
mise 2024.5.16

Also I don't know if I changed the output of the --version, but testing with a fresh install on my computer it doesn't show the word mise but only the version plus commit platform and date. Like this:

$ mise --version            
2024.8.12 linux-x64 (778f806 2024-08-20)

# old specific version
$ mise --version
2024.5.16 linux-x64 (8838098 2024-05-15)

Maybe that needs to be updated if it is outdated.