Add Update command

[G0rocks]

What's the problem this feature will solve?

When using pip, it is not intuitive how to update/upgrade packages and I just forgot how it is done so I wrote pip in the command line which tells you how to install packages and search for them but not how to update them.
Running pip to figure out how to update packages it tells you that you can run pip help for assistance but that shows you the same as when you run pip.
If you run pip install --help and read everything it tells you how to update packages but that is quite hidden and it is not intuitive to search for how to update things by running pip install --help

Describe the solution you'd like

I would like a new command for pip to be added which is update and maybe the alias upgrade since some people prefer that.
This command would run pip install --upgrade PACKAGE_NAME_HERE and when you run pip it would show up as one of the commands in the list of commands.

Alternative Solutions

If this feature is not what pip wants then another solution would be to modify the description of the install command from Install packages to Install and update packages or similar.
Though I do not think this solution is the best solution.

Additional context

I don't have any additional context and since I can not make this feature request without providing any then I would also like to suggest that this feature request form be modified so that the "Additional context" field would be changed from mandatory to optional.

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[notatallshaw]

This was originally suggested in #59, it was rejected back then because sufficient functionality was added to pip install via --upgrade and --upgrade-strategy.

I don't have a strong opinion on adding a dedicated command, but from my point of view PRs are welcome to add additional documentation.