solver: Call update_cache

DNF apparently doesn't check the expiration time on the cache unless you
call this first. It may help improve issues with the cache being out of
sync.

Internally dnf checks the mtime of the main repomd.xml file when using
baseurl, and it checks the hash values when using metalink so this
should not result in any noticeable extra slowdowns when things are
fresh.

osbuild/solver/dnf.py

@@ -86,6 +86,7 @@ class DNF(SolverBase):
                         repo_config.sslclientcert = modify_rootdir_path(repo_config.sslclientcert, root_dir)
                         repo_config.sslclientkey = modify_rootdir_path(repo_config.sslclientkey, root_dir)
 
+            self.base.update_cache()
             self.base.fill_sack(load_system_repo=False)
         except dnf.exceptions.Error as e:
             raise RepoError(e) from e