Update Vulkan dependency docs (#5178)

Vulkan deps are optional. vulkan-utils is replaced with vulkan-tools
since Debian 10.

Co-authored-by: Jeremy Rand <jeremyrand@danwin1210.de>

docs/how-to-build/how-to-build.md

@@ -36,15 +36,19 @@ Install required build dependencies:
 * g++
 * cmake
 * protocol buffer (protobuf) headers files and protobuf compiler
-* vulkan header files and loader library
 * glslang
+* (optional) vulkan header files and loader library # If building with Vulkan, without simplevk
 * (optional) opencv  # For building examples
 
 Generally if you have Intel, AMD or Nvidia GPU from last 10 years, Vulkan can be easily used.
 
 On some systems there are no Vulkan drivers easily available at the moment (October 2020), so you might need to disable use of Vulkan on them. This applies to Raspberry Pi 3 (but there is experimental open source Vulkan driver in the works, which is not ready yet). Nvidia Tegra series devices (like Nvidia Jetson) should support Vulkan. Ensure you have most recent software installed for best experience.
 
-On Debian, Ubuntu or Raspberry Pi OS, you can install all required dependencies using: 
+On Debian 10+, Ubuntu 20.04+, or Raspberry Pi OS, you can install all required dependencies using: 
+```shell
+sudo apt install build-essential git cmake libprotobuf-dev protobuf-compiler libvulkan-dev vulkan-tools libopencv-dev
+```
+On earlier Debian or Ubuntu, you can install all required dependencies using: 
 ```shell
 sudo apt install build-essential git cmake libprotobuf-dev protobuf-compiler libvulkan-dev vulkan-utils libopencv-dev
 ```