write update function

farm_agrikern.install

@@ -0,0 +1,22 @@
+**
+* Updates allowed taxonomy types.
+*/
+function farm_agrikern_update_1(&$sandbox) {
+    // Updates field storage config for field_custom_radio_buttons.
+    // @see https://www.drupal.org/node/2012896
+    // @see https://www.drupal.org/docs/8/api/update-api/updating-entities-and-fields-in-drupal-8#example-updating-a-field-from-an-obsolete-type-to-a-new-type
+    $old_config = FieldStorageConfig::loadByName('asset', 'crop_field');
+    $new_config = $old_config->createDuplicate();
+    $new_config->original = $new_config;
+    $new_config->enforceIsNew(FALSE);
+    $new_config
+    ->setSetting('target_bundle', 'plant_type')
+    ->save();
+    $old_config = FieldStorageConfig::loadByName('log', 'work_field');
+    $new_config = $old_config->createDuplicate();
+    $new_config->original = $new_config;
+    $new_config->enforceIsNew(FALSE);
+    $new_config
+    ->setSetting('target_bundle', 'work_type')
+    ->save();
+}