tests: qemucapabilities: Update capabilities of qemu-5.0.0 on x86_64

Update to v4.2.0-1858-gdb736e0437 which contains my commit for 'flat'
output of 'query-named-block-nodes'.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

tests/qemucapabilitiesdata/caps_5.0.0.x86_64.xml

@@ -227,7 +227,7 @@
   <version>4002050</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>43100241</microcodeVersion>
-  <package>v4.2.0-785-g3e08b2b9cb</package>
+  <package>v4.2.0-1858-gdb736e0437</package>
   <arch>x86_64</arch>
   <hostCPU type='kvm' model='base' migratability='yes'>
     <property name='vmx-entry-load-rtit-ctl' type='boolean' value='false'/>