v17.6.2

Fixed

• (brew) add assume_yes support (#2090)
• (powershell) skip step if there is a wrapper script (#2087)
• (brew) don't panic when linuxbrew owner uid has no passwd entry (#2063)
• (pip3) skip self-update on Termux (#2065)
• (nix) don't skip self-upgrade on non-NixOS Linux (#2072)