[#674] Support env var in ssh config

[yohamta]

Resolves #674

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 64.08%. Comparing base (87a33e6) to head (92f8db7). Report is 1 commits behind head on main.

Additional details and impacted files

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