fix: empty packageRules after applying to update

lib/workers/repository/updates/flatten.js

@@ -24,11 +24,14 @@ function flattenUpdates(config, packageFiles) {
             let updateConfig = mergeChildConfig(depConfig, update);
             delete updateConfig.updates;
             updateConfig = applyPackageRules(updateConfig);
+            // Now we're finished with these packageRules
+            updateConfig.packageRules = [];
             // apply major/minor/patch/pin/digest
             updateConfig = mergeChildConfig(
               updateConfig,
               updateConfig[updateConfig.updateType]
             );
+            // Apply again in case any were added by the updateType config
             updateConfig = applyPackageRules(updateConfig);
             updateConfig.depNameSanitized = updateConfig.depName
               ? updateConfig.depName