Summary should show self-update

[GideonBear]

Checklist

• I have searched the issue tracker for relevant or duplicate issues.

I want to suggest some general feature

Topgrade should show a succeeded self-update in the summary (of the child/execed process). Maybe good to wait until after #1147.

Possible implementation is by passing an undocumented flag to the child/execed process, like --internal-self-update-finished v1.2.3 v1.2.4

More information

• I am able and willing to implement this feature myself

[GideonBear]

Ref #1519