Update Install-Guide.md

apt is enough apt-get is no longer necessary

Author: dc-redeclipse

docs/Install-Guide.md

@@ -27,14 +27,14 @@ If you get a permission denied error during install, right click the installer a
 
 ### Standard Package
 - Install Red Eclipse's dependencies.
-    - Debian/Ubuntu: `sudo apt-get install curl libsdl2-mixer-2.0-0 libsdl2-image-2.0-0 libsdl2-2.0-0 libopenal1 libsndfile1`
+    - Debian/Ubuntu: `sudo apt install curl libsdl2-mixer-2.0-0 libsdl2-image-2.0-0 libsdl2-2.0-0 libopenal1 libsndfile1`
     - Fedora: `dnf install curl SDL2 SDL2_mixer SDL2_image`
 - [Download the tarball](/download/linux), move it to your home directory, and extract it with your file manager, an archive utility, or the terminal command `tar -jxvf redeclipse_X.Y.Z_nix.tar.bz2`.
 - Enter the extracted folder (redeclipse-X.Y.Z) and run `redeclipse.sh` to launch Red Eclipse.
 
 ### From Source
 - Install additional dependencies to compile with:
-    - Debian/Ubuntu: `sudo apt-get install make g++ curl libsdl2-mixer-dev libsdl2-image-dev libsdl2-dev libfreetype-dev libopenal-dev libsndfile-dev`
+    - Debian/Ubuntu: `sudo apt install make g++ curl libsdl2-mixer-dev libsdl2-image-dev libsdl2-dev libfreetype-dev libopenal-dev libsndfile-dev`
 
 From the command line:
 - Clone the repository and its submodules with `git clone --recurse-submodules https://github.com/redeclipse/base`