Limit conan ci build to x86_64.

script/conan_build.sh

@@ -3,6 +3,8 @@
 set -ex
 
 export CONAN_DOCKER_IMAGE=conanio/gcc${CONAN_GCC_VERSIONS}
+export CONAN_ARCHS="x86_64"
+export CONAN_BUILD_TYPES=Release
 
 pip install -U conan conan_package_tools
 python build.py