Add rel="noopener noreferrer" to links

client/src/components/voronoi/entity/Empty.js

@@ -10,25 +10,34 @@ export default function Empty(props) {
       <Card.Body>
         <Card.Text>
           Mímir is a visual platform to explore the{' '}
-          <a target='_blank' href='https://www.bar.admin.ch/bar/en/home.html'>
+          <a
+            target="_blank"
+            rel="noopener noreferrer"
+            href="https://www.bar.admin.ch/bar/en/home.html"
+          >
             Swiss Federal Archives
           </a>
           . It aggregates the results according to the{' '}
           <a
-            target='_blank'
-            href='https://www.recherche.bar.admin.ch/recherche/#/en/search/archive-plan'
+            target="_blank"
+            rel="noopener noreferrer"
+            href="https://www.recherche.bar.admin.ch/recherche/#/en/search/archive-plan"
           >
             archive plan
           </a>{' '}
           and presents them with{' '}
-          <a href='https://pubsys.mmsp-kn.de/pubsys/publishedFiles/BaDe05b.pdf' target='_blank'>
+          <a
+            target="_blank"
+            rel="noopener noreferrer"
+            href="https://pubsys.mmsp-kn.de/pubsys/publishedFiles/BaDe05b.pdf"
+          >
             Voronoi treemaps
           </a>
           .
         </Card.Text>
       </Card.Body>
       <Card.Header as={'h6'}>Instructions</Card.Header>
-      <ListGroup variant='flush'>
+      <ListGroup variant="flush">
         <ListGroup.Item>
           Enter your text query in the <b>search bar</b>
         </ListGroup.Item>