Try even older conan for CentOS 7

Author: garyo

.github/workflows/build.yml

@@ -42,7 +42,7 @@ jobs:
             has_cmake_presets: false
             buildtype: Release
             # use old conan version for CentOS 7
-            conan_version: 2.15.0
+            conan_version: 2.10.3
             cxx-standard: 17
             cxx-compiler: clang++
             cc-compiler: clang
@@ -60,7 +60,7 @@ jobs:
             has_cmake_presets: false
             buildtype: Release
             # use old conan version for CentOS 7
-            conan_version: 2.15.0
+            conan_version: 2.10.3
             cxx-standard: 17
             cxx-compiler: clang++
             cc-compiler: clang