Update CMake version for CMP0090
Summary:
[CMP0090](https://cmake.org/cmake/help/latest/policy/CMP0090.html) was introduced in CMake version 3.15. The CMake version guard
should be greater or equal to 3.15.
My cmake version is 3.14.5, and run into the following error.
```
cmake --version
cmake version 3.14.5
```
```
CMake Error at CMakeLists.txt:338 (cmake_policy):
Policy "CMP0090" is not known to this version of CMake.
-- Configuring incomplete, errors occurred!
Test Plan:
```
cmake
```
Signed-off-by: lhuang04 <lhuang04@fb.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index cf74af5..210aba4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -330,7 +330,7 @@
DESTINATION "cmake"
FILE "MbedTLSTargets.cmake")
-if(CMAKE_VERSION VERSION_GREATER 3.14)
+if(CMAKE_VERSION VERSION_GREATER 3.15 OR CMAKE_VERSION VERSION_EQUAL 3.15)
# Do not export the package by default
cmake_policy(SET CMP0090 NEW)