chore: replacing the links to the letter

Signed-off-by: blam <ben@blam.sh>

microsite/pages/en/community.js

@@ -76,7 +76,7 @@ const Background = props => {
                 <li>
                   <Block.Paragraph style={{ marginBottom: '0' }}>
                     Subscribe to the{' '}
-                    <a href="https://mailchi.mp/spotify/backstage-community">
+                    <a href="https://info.backstage.spotify.com/newsletter_subscribe">
                       Community newsletter
                     </a>
                   </Block.Paragraph>
@@ -122,7 +122,7 @@ const Background = props => {
                 The official monthly Backstage newsletter. Don't miss the latest
                 news from your favorite project!
               </Block.Paragraph>
-              <Block.LinkButton href="https://mailchi.mp/spotify/backstage-community">
+              <Block.LinkButton href="https://info.backstage.spotify.com/newsletter_subscribe">
                 Subscribe
               </Block.LinkButton>
             </Block.TextBox>

microsite/pages/en/index.js

@@ -25,7 +25,7 @@ class Index extends React.Component {
             <Banner.Dismissable storageKey="2022-03-16-newsletter-cta">
               <div>
                 🗞️ Want to stay up to date with Backstage? Sign up for our{' '}
-                <a href="https://mailchi.mp/spotify/backstage-community">
+                <a href="https://info.backstage.spotify.com/newsletter_subscribe">
                   Newsletter
                 </a>
                 !

microsite/pages/en/live.js

@@ -64,7 +64,7 @@ const Background = props => {
                 Good First Issues
               </a>
               <br />- Subscribe to the{' '}
-              <a href="https://mailchi.mp/spotify/backstage-community">
+              <a href="https://info.backstage.spotify.com/newsletter_subscribe">
                 Community newsletter
               </a>
               <br />- Join the{' '}