Update CMake minimum version(s) to match main CMakeLists.txt

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/programs/test/cmake_package/CMakeLists.txt b/programs/test/cmake_package/CMakeLists.txt
index 518d2e9..019e6e7 100644
--- a/programs/test/cmake_package/CMakeLists.txt
+++ b/programs/test/cmake_package/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8.12)
+cmake_minimum_required(VERSION 3.5.1)
 
 #
 # Simulate configuring and building Mbed TLS as the user might do it. We'll
diff --git a/programs/test/cmake_package_install/CMakeLists.txt b/programs/test/cmake_package_install/CMakeLists.txt
index fb5ad51..6070a6c 100644
--- a/programs/test/cmake_package_install/CMakeLists.txt
+++ b/programs/test/cmake_package_install/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8.12)
+cmake_minimum_required(VERSION 3.5.1)
 
 #
 # Simulate configuring and building Mbed TLS as the user might do it. We'll
diff --git a/programs/test/cmake_subproject/CMakeLists.txt b/programs/test/cmake_subproject/CMakeLists.txt
index a9fcfde..3c3cba3 100644
--- a/programs/test/cmake_subproject/CMakeLists.txt
+++ b/programs/test/cmake_subproject/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.6)
+cmake_minimum_required(VERSION 3.5.1)
 
 # Test the target renaming support by adding a prefix to the targets built
 set(MBEDTLS_TARGET_PREFIX subproject_test_)