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
Now `:PlugInstall!` and `:PlugUpdate!` forces to update submodules.
`:PlugInstall!` now also checks out to new specified branch, tag, or
commit.
Also added tests for changing branch, tag, or commit.
* Main differences from ruby are inside Command class, notably it
poll/sleeps on the subprocess to check output & timeout.
* Another difference, interrupt is not instaneous due to checking var.
* Otherwise, I mainly just mirrored code into objects.
* Note that due to GVim freeze, disabling use on Windows
