rpm: Set pkgverify_level to digest

This was changed to all in rpm 6.0.0, which means that rpm is checking
for signatures from dnf/zypper repos that have gpgcheck=0. dnf5 was updated
to deal with this but for some reason the fix isn't working in Arch and zypper
doesn't deal with this at all, so revert back to the previous level until
package managers can actually deal with this.

Author: daandemeyer

mkosi/installer/rpm.py

@@ -91,6 +91,10 @@ def setup_rpm(
     if dbbackend:
         (confdir / "macros.db_backend").write_text(f"%_db_backend {dbbackend}")
 
+    # TODO: Drop when zypper and dnf5 correctly disable signature checks for gpgcheck=0 repositories.
+    if not (confdir / "macros.pkgverify_level").exists():
+        (confdir / "macros.pkgverify_level").write_text("%_pkgverify_level digest")
+
     if context.config.distribution == Distribution.opensuse or (
         context.config.distribution.is_centos_variant() and context.config.release == "9"
     ):