glibmm: update to 2.56.0 (#3804)

This updates glibmm to 2.56.0.

mingw-w64-glibmm/PKGBUILD

@@ -3,7 +3,7 @@
 _realname=glibmm
 pkgbase=mingw-w64-${_realname}
 pkgname="${MINGW_PACKAGE_PREFIX}-${_realname}"
-pkgver=2.54.1
+pkgver=2.56.0
 pkgrel=1
 pkgdesc="Glib-- (glibmm) is a C++ interface for glib (mingw-w64)"
 arch=('any')
@@ -13,7 +13,7 @@ makedepends=("${MINGW_PACKAGE_PREFIX}-gcc" "${MINGW_PACKAGE_PREFIX}-pkg-config")
 depends=("${MINGW_PACKAGE_PREFIX}-libsigc++" "${MINGW_PACKAGE_PREFIX}-glib2")
 options=('staticlibs' 'strip')
 source=("https://download.gnome.org/sources/glibmm/${pkgver%.*}/glibmm-${pkgver}.tar.xz")
-sha256sums=('7cc28c732b04d70ed34f0c923543129083cfb90580ea4a2b4be5b38802bf6a4a')
+sha256sums=('6e74fcba0d245451c58fc8a196e9d103789bc510e1eee1a9b1e816c5209e79a9')
 
 prepare() {
   cd "${srcdir}"/${_realname}-${pkgver}