Add Conflicts to prevent upgrades

Since _kernel_ is an `installonly` package, "upgrading" actually
installs a new version instead of replacing the installed version.
Because of this, the `Requires` tag of _gasket-driver_ does not prevent
upgrading to a new version of the kernel, as the requirement will still
be satisfied by the old version.

To fully prevent upgrading to a new kernel for which there is no
_gasket-driver_ (which would prevent Frigate from starting after the
reboot), we need to add a `Conflicts` tag.  This will not allow RPM to
install a version of _kernel_ newer than the one that matches
_gasket-driver_.

ci/Jenkinsfile

@@ -13,7 +13,7 @@ pipeline {
             regexpFilterExpression: 'kernel-.*',
             regexpFilterText: '$nvr',
             silentResponse: true,
-            tokenCredentialId: 'webhook-trigger',
+            tokenCredential: 'webhook-trigger',
         )
     }