pacman: require databases to be signed

We used the defaults from Arch, but Arch doesn't sign its databases.
We do sign them, so there is no reason to not enforce this.

Fixes #2453

pacman/PKGBUILD

@@ -4,7 +4,7 @@
 
 pkgname=pacman
 pkgver=5.2.2
-pkgrel=20
+pkgrel=21
 pkgdesc="A library-based package manager with dependency support (MSYS2 port)"
 arch=('i686' 'x86_64')
 url="https://www.archlinux.org/pacman/"
@@ -62,7 +62,7 @@ source=(https://sources.archlinux.org/other/pacman/${pkgname}-${pkgver}.tar.gz
 validpgpkeys=('6645B0A8C7005E78DB1D7864F99FFE0FEAE999BD'  # Allan McRae <allan@archlinux.org>
               'B8151B117037781095514CA7BBDFFC92306B1121') # Andrew Gregory (pacman) <andrew@archlinux.org>
 sha256sums=('bb201a9f2fb53c28d011f661d50028efce6eef2c1d2a36728bdd0130189349a0'
-            '9015f0a87639dcfe597e68996584d58d5f5177b478f5e3afbfb6081a22fc93f5'
+            'f5a84c5642d57044ddb40387822bfcb01bdbdcd885b46bc93d116aaf0e5741a6'
             '822af13248f04690377cd193370f33ac2f00a41234ead9cf3b7e5d5aba8bd0c5'
             'e533985757a4fef1e72c3349eb62aebbd14c1d457faf10306218cf637b207030'
             '2bd27c3fc5443b367e5025c9b9a35670b02202e48e92eead90755fef8d08fa83'

pacman/pacman.conf

@@ -37,7 +37,7 @@ CheckSpace
 # By default, pacman accepts packages signed by keys that its local keyring
 # trusts (see pacman-key and its man page), as well as unsigned packages.
 #SigLevel = Never
-SigLevel    = Required DatabaseOptional
+SigLevel    = Required
 LocalFileSigLevel = Optional
 #RemoteFileSigLevel = Required