speedtest-cli: depend on python@3.10

[branchvincent]

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This currently relies on Python 2: https://github.com/sivel/speedtest-cli/blob/22210ca35228f0bbcef75a7c14587c4ecb875ab4/speedtest.py#L1

Part of #93940

[BrewTestBot]

🤖 A scheduled task has triggered a merge.