Fix the pipx-package inject command

[benklett]

As per #607 pipx-package errors with the following, when being used with injections:

pipx: error: unrecognized arguments: 

The reason for this behaviour is a change in pipx. The resulting backwards incompatibility is discussed here: pypa/pipx#1444

There someone metioned the following:

Seems there is no easy solution for back-compatibility while keeping the --requirement feature. :-(

For this reason I propose to change the order to fix the feature for the time being.

Hopefully I am not missing something important.

[evilhamsterman]

This project is not associated with the devcontainer project and appears to have been abandoned #628 . The official project has removed all devcontainer-contrib features from their listing. devcontainers/devcontainers.github.io#451. There is a fork that is being worked on to update and maintain the features https://github.com/devcontainers-extra/features