BC: remove support for end-of-lice npm

[jkowalleck]

some versions of npm cli are end of life:

• 6
• 7 -- last release in 2021 -- https://github.com/npm/cli/releases/tag/v7.24.2
• 8 -- last release in 2023 -- https://github.com/npm/cli/releases/tag/v8.19.4

goal: remove support for this