Linux: Fix gradle issue with Android builds on ubuntu* systems.

- Updated installer script to grab the latest version of Gradle, which fixes
the Android build issues on Ubuntu* based distros.
- Added git step to installer script, as some distros do not include it by default.
This fixes a potential issue with the sample code not being downloaded by the
installer.

Author: Danny Glover

platform/linux/Solar2DSimulator/install.sh

@@ -58,6 +58,7 @@ mv Solar2DBuilder ~/.local/share/Corona/Native/Corona/lin/bin/
 # install required dependencies via Apt
 if [[ $USE_APT == 1 ]]; then
   # nake sure we have the latest package lists
+  sudo add-apt-repository ppa:cwchien/gradle -y
   sudo apt-get update
   # install dependencies
   sudo apt-get install build-essential -y
@@ -80,10 +81,12 @@ if [[ $USE_APT == 1 ]]; then
   sudo apt-get install openjdk-8-jdk-headless -y
   sudo apt-get install openjdk-8-jre-headless -y
   sudo apt-get install unzip -y
+  sudo apt-get install git -y
   sudo apt-get install p7zip -y
   sudo apt-get install p7zip-full -y
   sudo apt-get install lua5.1 -y
   sudo apt-get install gradle -y
+  sudo apt upgrade gradle
 # install required dependencies via Pacman
 elif [[ $USE_PACMAN == 1 ]]; then
   sudo pacman -Sy base-devel --noconfirm
@@ -106,6 +109,7 @@ elif [[ $USE_PACMAN == 1 ]]; then
   sudo pacman -Sy jdk14-openjdk --noconfirm
   sudo pacman -Sy jre14-openjdk --noconfirm
   sudo pacman -Sy unzip --noconfirm
+  sudo pacman -Sy git --noconfirm
   sudo pacman -Sy p7zip --noconfirm
   sudo pacman -Sy lua51 --noconfirm
   sudo pacman -Sy gradle --noconfirm