Fix upgrade

[maniackcrudelis]

Problem

• Upgrade fails with error: "ImportError: No module named _internal"

Solution

• Do not reinstall pip to avoid a conflict between pip versions.

PR Status

Work finished. Package_check, basic tests and upgrade from last version OK.
Could be reviewed and tested.

Validation

---

Minor decision

• Upgrade previous version :
• Code review :
• Approval (LGTM) : Josué
• Approval (LGTM) :
• CI succeeded :
  When the PR is mark as ready to merge, you have to wait for 3 days before really merge it.

[JimboJoe]

Isn't this PR already included in #32?

[maniackcrudelis]

Huh, yes it is.
I probably cloned this PR to made the other one, in order to try the upgrade.

[JimboJoe]

So, as the other one will get merged, are you OK with closing this one?

[maniackcrudelis]

Yes, we can close this one as we merge the other one.

[JimboJoe]

Closing this PR as #32 got merged.

[frju365]

I didn't understand, why merging this... or what did you mean by "close" . :-??

[JimboJoe]

Well I actually closed it, but the two PR seem linked somehow (14 update branch was probably created from fix_upgrade branch), hence that surprising "JimboJoe merged commit 284b297 into testing ".