How to configure a webhook to 'clear cache and build master'

[membersheep]

I'm working on a gatsby website. In the homepage I have a carousel which loads some elements with a static graphql query and i filter them with a isFuture schema customization:

exports.createSchemaCustomization = ({ actions, schema, getNode }) => {
  actions.createTypes([
    schema.buildObjectType({
      name: 'StrapiEvent',
      interfaces: ['Node'],
      fields: {
        isFuture: {
          type: 'Boolean!',
          resolve: source => new Date(source.date) > new Date(),
        },
      },
    }),
  ]);
};

The site build is triggered every day by a webhook. The problem is that the current date seems not to be updated at each build, but if I manually run clear cache and build master instead of just pressing the Trigger Build button it works correctly.
Is there a way to configure the webhook to run clear cache and build master instead of just Trigger Build ?
Thanks