Fixes

• nvm install-latest-npm: npm v6.14.18 can not be installed from npm < v4.4.4
• ensure this variable is bound
• debug: correct mistaken -V to --version from #2922
• debug: awk: not an option: --version (#2922)
• grep: warning: stray \ before / (#2919)
• improve backward compatibility for non-gnu awk (#2917)
• fix nvm install error unknown condition: -ne (#2915)

Tests

• update test mocks (#2933)
• move installation_node tests back to xenial
• move tests that fail on focal to a separate suite that runs on xenial
• update travis to use focal
• [actions] fix latest-npm tests so they use this repo’s nvm instead of the last published one
• fix nvm_list_aliases test to use mocks for LTS aliases

Docs

• [meta] Improve contributors documentation (#2791)
• [Docs] added WSL troubleshooting with solution to (6) Could not resolve host: raw.githubusercontent.com (#2961)

Refactors

• add nvm_wrap_with_color_code; allow no color code