README: add Ubuntu specific package names

It could be hard for Ubuntu/Debian users to find the correct packages
for the dependencies.

Thanks @kgilmer

Signed-off-by: Yuxuan Shui <[email protected]>

README.md

@@ -31,7 +31,7 @@ See [Releases](https://github.com/yshui/compton/releases)
 
 ### Dependencies
 
-Assuming you already have all the usual building tools installed (e.g. gcc, meson, ninja, etc.), you still need:
+Assuming you already have all the usual building tools installed (e.g. gcc, python, meson, ninja, etc.), you still need:
 
 * libx11
 * libx11-xcb
@@ -57,6 +57,12 @@ Assuming you already have all the usual building tools installed (e.g. gcc, meso
 * libev
 * uthash
 
+On Debian based distributions (e.g. Ubuntu), the list of needed packages are
+
+```
+libxext-dev libxcb1-dev libxcb-damage0-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-render-util0-dev libxcb-render0-dev libxcb-randr0-dev libxcb-composite0-dev libxcb-image0-dev libxcb-present-dev libxcb-xinerama0-dev libpixman-1-dev libdbus-1-dev libconfig-dev libxdg-basedir-dev libgl1-mesa-dev  libpcre2-dev  libevdev-dev uthash-dev libevdev2
+```
+
 To build the documents, you need `asciidoc`
 
 ### To build