Update Vulkan SDK version in TravisCI configuration

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index 96a178a..2a68740 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -19,7 +19,7 @@
   - tar -xzvf premake-5.0.0-alpha11-linux.tar.gz

   - sudo apt-get -qq update

   - sudo apt-get install -y libassimp-dev libglm-dev graphviz libxcb-dri3-0 libxcb-present0 libpciaccess0 cmake libpng-dev libxcb-dri3-dev libx11-dev libx11-xcb-dev libmirclient-dev libwayland-dev libxrandr-dev

-  - export VK_VERSION=1.1.82.1

+  - export VK_VERSION=1.2.131.1

   - wget -O vulkansdk-linux-x86_64-$VK_VERSION.tar.gz https://sdk.lunarg.com/sdk/download/$VK_VERSION/linux/vulkansdk-linux-x86_64-$VK_VERSION.tar.gz

   - tar zxf vulkansdk-linux-x86_64-$VK_VERSION.tar.gz

   - export VULKAN_SDK=$TRAVIS_BUILD_DIR/$VK_VERSION/x86_64