follow instructions on msys2

Author: bvogelzang

appveyor.yml

@@ -21,6 +21,11 @@ install:
   - gem --version
 
   # update all packages on the system
+  # https://www.msys2.org/news/#2020-06-29-new-packagers
+  - C:\msys64\usr\bin\curl -O http://repo.msys2.org/msys/x86_64/msys2-keyring-r21.b39fb11-1-any.pkg.tar.xz
+  - C:\msys64\usr\bin\curl -O http://repo.msys2.org/msys/x86_64/msys2-keyring-r21.b39fb11-1-any.pkg.tar.xz.sig
+  - ridk exec bash -c "pacman-key --verify msys2-keyring-r21.b39fb11-1-any.pkg.tar.xz.sig"
+  - ridk exec bash -c "pacman -U --noconfirm --config <(echo) msys2-keyring-r21.b39fb11-1-any.pkg.tar.xz"
   - C:\msys64\usr\bin\bash -lc "yes | pacman -Syuu"
 
   # prevent freetds to link to wrong ws2_32 lib on i686-w64-mingw32