Update assertion as the <button> has children, not value

tests/tests_e2e/cypress/integration/main.js

@@ -53,7 +53,7 @@ describe('First Test', () => {
         .should('contain', 'Server Options');
 
       cy.get('button.btn.btn-jupyter')
-        .should('have.attr', 'value', 'Start').click();
+        .should('contain', 'Start').click();
 
       // Minimal check that JupyterLab has opened
       cy.get('div#jp-MainLogo', { timeout: 60000 }).should('exist').wait(4000);