appveyor.yml - msys2 update code

As AppVeyor's MSYS2 install gets out of date, this may require 'special' code...

This code also adds updating the database, which currently updates gcc from 9.1.0 to 9.2.0.

appveyor.yml

@@ -98,8 +98,8 @@ for:
     - SET PATH=%ruby_path%\bin;C:\msys64\%MSYSTEM%\bin;C:\msys64\usr\bin;%PATH%
     - ruby --version
   build_script:
-    - pacman -S --noconfirm --needed --noprogressbar --nodeps mingw-w64-x86_64-toolchain
-    - pacman -S --noconfirm --needed --noprogressbar mingw-w64-x86_64-gdbm mingw-w64-x86_64-gettext mingw-w64-x86_64-gmp mingw-w64-x86_64-libffi mingw-w64-x86_64-libyaml mingw-w64-x86_64-openssl mingw-w64-x86_64-ragel mingw-w64-x86_64-readline mingw-w64-x86_64-zlib
+    - pacman -Sy --noconfirm --noprogressbar --needed mingw-w64-x86_64-toolchain
+    - pacman -S  --noconfirm --noprogressbar --needed mingw-w64-x86_64-gdbm mingw-w64-x86_64-gmp mingw-w64-x86_64-libffi mingw-w64-x86_64-libyaml mingw-w64-x86_64-openssl mingw-w64-x86_64-ragel mingw-w64-x86_64-readline mingw-w64-x86_64-zlib
     - cd %APPVEYOR_BUILD_FOLDER%
     - set CFLAGS=-march=%MSYS2_ARCH:_=-% -mtune=generic -O3 -pipe
     - set CXXFLAGS=%CFLAGS%