qt5 (meta): bump to 5.15.3

this doesn't change much, but all packages are now at 5.15.3 so avoid the confusion

mingw-w64-qt5/PKGBUILD

@@ -4,8 +4,8 @@
 _realname=qt5
 pkgbase="mingw-w64-${_realname}"
 pkgname=("${MINGW_PACKAGE_PREFIX}-${_realname}" "${MINGW_PACKAGE_PREFIX}-${_realname}-debug")
-pkgver=5.15.2
-pkgrel=15
+pkgver=5.15.3
+pkgrel=1
 arch=('any')
 mingw_arch=('mingw32' 'mingw64' 'ucrt64' 'clang64' 'clang32')
 pkgdesc="Meta package for Qt5 components (mingw-w64)"