added e2e tests (#298)

- added e2e tests for
  - banner
  - history
  - intro
  - language
  - link
- added e2e workflow
- added cypress badge to README

cypress/integration/history.spec.ts

@@ -0,0 +1,35 @@
+describe('History', () => {
+  beforeEach(() => {
+    cy.visit('/history')
+  })
+
+  describe('History Mode', () => {
+    it('Cards', () => {
+      cy.get('div.card')
+    })
+
+    it('Table', () => {
+      cy.get('i.fa-table')
+        .click()
+      cy.get('table.history-table')
+    })
+  })
+
+  describe('Pinning', () => {
+    it('Cards', () => {
+      cy.get('.fa-thumb-tack')
+        .first()
+        .click()
+      cy.get('.modal-dialog')
+        .should('be.visible')
+    })
+
+    it('Table', () => {
+      cy.get('.fa-thumb-tack')
+        .first()
+        .click()
+      cy.get('.modal-dialog')
+        .should('be.visible')
+    })
+  })
+})