neural-amp-modeler-lv2: patch math_approx cmake minimum version for pipeline

Author: franconassis

plugins/package/neural-amp-modeler-lv2/06_fix-math-approx-cmake-version.patch

@@ -0,0 +1,8 @@
+--- a/deps/NeuralAudio/deps/math_approx/CMakeLists.txt
++++ b/deps/NeuralAudio/deps/math_approx/CMakeLists.txt
+@@ -1,4 +1,4 @@
+-cmake_minimum_required(VERSION 3.18)
++cmake_minimum_required(VERSION 3.16)
+ project(math_approx VERSION 1.0.0 LANGUAGES CXX)
+
+ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake/)