chcp parsing is fragile because of the system locale. There's no convenient way to parse out the codepage value without regex just by relying on cmd.exe builtins and default binaries in PATH.
Vim can be used to parse chcp output but it requires an additional `system` per `s:system` and `chcp` can change within the same console so caching the value won't work on the terminal.
Powershell supports regex but it has a long startup even with `-NoProfile` so running it when `&shell` is not powershell slows down `:PlugInstall` more.
Travis defaults to it since this year.
Ubuntu trusty reached EOL since April 2019.
Ubuntu bionic provides Vim 8.
Simplify OS install with Travis' apt addon
so that only Vim nightly will be compiled from source.
Ubuntu 14.04.6 provides ruby v.1.9.3, not 1.8.x or older.
Use it to test the ruby provider for backward compatibility.
Signed-off-by: Jan Edmund Lazo <jan.lazo@mail.utoronto.ca>
Excerpt from `:h shell-powershell`:
To use powershell (on Windows):
set shell=powershell shellquote=( shellpipe=\| shellxquote=
set shellcmdflag=-NoLogo\ -NoProfile\ -ExecutionPolicy\ RemoteSigned\ -Command
set shellredir=\|\ Out-File\ -Encoding\ UTF8
Close#635Close#668Close#539
Use a temporary batchfile for :!, system(), and jobs and run it in cmd.exe.
This bypasses Vim/Neovim issues in Windows and reduces the need to set more options.
Also, s:shellesc_cmd works in a batchfile only.
Set shellredir for system() in Windows
$SHELL sets the default value of 'shell' (see :h 'shell').
This affects shellredir but cmd.exe requires '>%s 2>&1'.
Jan Edmund LazoandGitHub
