Update PATH: libexec is not available, atom is removed, and 7z is added to packages

[heetbeet]

The path additions are a bit outdated:

juliawin/bin/activate-juliawin-environment.bat

Line 29 in fe27565

set "PATH=%juliawin_packages%\julia\libexec;%juliawin_packages%\julia\bin;%juliawin_packages%\curl\bin;%juliawin_packages%\vscode;%juliawin_packages%\atom\resources\cli;%PATH%"