Kokoro: update CMake to latest version

tests/kokoro/gcp_ubuntu/continuous.sh

@@ -5,10 +5,18 @@ cd git/SwiftShader
 set -e # Fail on any error.
 set -x # Display commands being run.
 
+# Update CMake
+sudo aptitude purge -yq cmake
+wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | sudo apt-key add -
+sudo apt-add-repository 'deb https://apt.kitware.com/ubuntu/ xenial main'
+sudo aptitude update -yq
+sudo aptitude install -yq cmake
+cmake --version
+
 # Specify we want to build with GCC 7
 sudo add-apt-repository ppa:ubuntu-toolchain-r/test
-sudo apt-get update
-sudo aptitude install -y gcc-7 g++-7
+sudo aptitude update -yq
+sudo aptitude install -yq gcc-7 g++-7
 sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 100 --slave /usr/bin/g++ g++ /usr/bin/g++-7
 sudo update-alternatives --set gcc "/usr/bin/gcc-7"
 

tests/kokoro/gcp_windows/continuous.bat

@@ -20,6 +20,10 @@ SET LESS_DEBUG_INFO=1
 cd %SRC%\build
 if !ERRORLEVEL! neq 0 exit /b !ERRORLEVEL!
 
+rem Update CMake
+choco upgrade cmake -y --limit-output --no-progress
+cmake --version
+
 cmake .. ^
     -G "Visual Studio 15 2017 Win64" ^
     -Thost=x64 ^

tests/kokoro/macos/continuous.sh

@@ -5,6 +5,8 @@ set -e
 # Display commands being run.
 set -x
 
+cmake --version
+
 cd git/SwiftShader
 
 mkdir -p build && cd build