Add GPU backend and linux info on template (#968)

.github/ISSUE_TEMPLATE.md

@@ -13,12 +13,14 @@
 - CPU backend:              <!-- As of today Vita3K uses two CPU backend engines to run games: Unicorn and Dynarmic.
                             When testing games Dynarmic should be prefered as it normally gives better results than Unicorn
                             You can change the CPU backend on the emu settings -->
+- GPU backend: <!-- Vita3K has the option to choose bewteen Vulkan and OpenGL, there is no superior
+							option and one can have better results than other -->
 
                           
 
 # Test environment summary
 - Tested by: ?
-- OS: Windows 10/macOS?
+- OS: Windows 10/macOS/Linux Distro, Kernel Version?
 - CPU: AMD/Intel?
 - GPU: AMD/NVIDIA/Intel?
 - RAM: ? GB