add conan profile definition for MinGW

conan_profile_mingw8.1

@@ -0,0 +1,17 @@
+# this is a conan profile for MinGW GCC 8.1
+[settings]
+os=Windows
+os_build=Windows
+arch=x86_64
+arch_build=x86_64
+compiler=gcc
+compiler.version=8.1
+compiler.exception=seh
+compiler.libcxx=libstdc++11
+compiler.threads=posix
+build_type=Release
+[options]
+[build_requires]
+mingw_installer/1.0@conan/stable
+msys2_installer/latest@bincrafters/stable
+[env]