fix: Header Component - Replaced class by func. comp (#142)

* refactor: replaced class by func.comp

* refactor: replacing jest test by react-testing-library

* refactor: added test todos

* feat: added more unit tests

* fix: fixed tooltip import

* fix: fixed test

* fix: fixed typo

* fix: fixed imports

src/components/Header/HeaderGreetings.tsx

@@ -0,0 +1,18 @@
+import React from 'react';
+
+import Label from '../Label';
+
+import { Greetings } from './styles';
+
+interface Props {
+  username: string;
+}
+
+const HeaderGreetings: React.FC<Props> = ({ username }) => (
+  <>
+    <Greetings>{'Hi,'}</Greetings>
+    <Label capitalize={true} text={username} weight="bold" />
+  </>
+);
+
+export default HeaderGreetings;