Fix MinGW build on Appveyor by changing search path order
Fix MinGW build on Appveyor by changing search path order

C:\MinGW\bin should go first to prevent executables from older
version of MinGW in C:\MinGW\mingw32 being picked up.

alabuzhev/fmt,mojoBrendan/fmt,blaquee/cppformat,blaquee/cppformat,mojoBrendan/fmt,wangshijin/cppformat,Jopie64/cppformat,dean0x7d/cppformat,lightslife/cppformat,nelson4722/cppformat,seungrye/cppformat,alabuzhev/fmt,Jopie64/cppformat,dean0x7d/cppformat,Jopie64/cppformat,nelson4722/cppformat,nelson4722/cppformat,wangshijin/cppformat,blaquee/cppformat,cppformat/cppformat,mojoBrendan/fmt,cppformat/cppformat,lightslife/cppformat,seungrye/cppformat,seungrye/cppformat,dean0x7d/cppformat,cppformat/cppformat,wangshijin/cppformat,lightslife/cppformat,alabuzhev/fmt