157: Handle resizing in hello-triangle r=kvark a=quadrupleslap
Nothing gets drawn on my computer unless the swap chain is resized along with the window.
```
$ uname -a
Linux red 5.3.7-arch1-1-ARCH #1 SMP PREEMPT Fri Oct 18 00:17:03 UTC 2019 x86_64 GNU/Linux
$ wmctrl -m
Name: bspwm
Class: wm
PID: 665
Window manager's "showing the desktop" mode: N/A
```
Co-authored-by: Ram Kaniyur <quadrupleslap@gmail.com>