[gnome-system-monitor] Updated developer docs

[Robert Roth <robertroth src gnome org>]

commit 53b0242e4e60a763bbd8e3f1fa4799ec6daa7c37
Author: Robert Roth <robert roth off gmail com>
Date:   Fri Jan 8 09:20:40 2021 +0200

    Updated developer docs

 AUTHORS   |  3 ++-
 README.md | 14 +++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/AUTHORS b/AUTHORS
index 12e6f22d..801f3274 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -1,7 +1,8 @@
 Kevin Vandersloot <kfv101 psu edu>
 Erik Johnsson <zaphod linux nu> - icon support
 Jorgen Scheibengruber
-Benoît Dejean <benoit placenet org> - maintainer
+Benoît Dejean <benoit placenet org>
 Paolo Borelli <pborelli katamail com>
 Baptiste Mille-Mathias - artwork
 Karl Lattimer <karl qdh org uk>
+Robert Roth <robert roth off gmail com> - maintainer
diff --git a/README.md b/README.md
index 1ec33042..54fdafb4 100644
--- a/README.md
+++ b/README.md
@@ -15,16 +15,24 @@ The steps described below show how to compile and install Gnome-System-Monitor f
 ### Install required dependencies
 To build the application, the following dependencies are required:
 
-Debian/Ubuntu: `sudo apt-get install meson gettext appstream-util itstool libglibmm-2.4-dev libgtkmm-3.0-dev 
libgtop2-dev librsvg2-dev libxml2-dev`
+#### apt-get (Debian/Ubuntu/derivatives - deb-based package management)
+Use the following command to install dependencies:
+`sudo apt-get install meson gettext appstream-util itstool libglibmm-2.4-dev libgtkmm-3.0-dev libgtop2-dev 
librsvg2-dev libxml2-dev`
 
-Optional dependencies:
-- libgksu2 - recommended
+#### dnf (Fedora/Centos/etc - rpm-based package management)
+Use the following command to install dependencies:
+`sudo dnf install meson gettext appstream itstool glibmm24-devel gtkmm30-devel libgtop2-devel librsvg2-devel 
libxml2-devel`
+
+#### Optional dependencies:
+- polkit - recommended
+- gksu2
 - libgnomesu
 - libselinux
 - lsb_release in PATH - recommended on linux
 - libsystemd-dev
 - libwnck
 
+
 ### Building and installing
 Before following the steps below, clone the repository and change to its working directory.