Update the Cmake requirement to be same as upstream LLVM.

Diptorup Deb · Diptorup Deb · commit 442f5cedc9c3 · 2022-05-03T16:10:03.000-05:00
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-cmake_minimum_required(VERSION 3.15)
+cmake_minimum_required(VERSION 3.13.4)
 
 project(mlir-extensions)
 
