CI test: bump conan_version on MacOS

Author: garyo

.github/workflows/build.yml

@@ -116,7 +116,7 @@ jobs:
             os: macos-latest
             has_cmake_presets: true
             buildtype: Release
-            conan_version: 2.1.0
+            conan_version: 2.20.1
             cxx-standard: 17
             cxx-compiler: clang++
             cc-compiler: clang