Rework the contribute/get involved section to match the mock-up

Signed-off-by: Benoit Donneaux <benoit@leastauthority.com>

src/_sass/_custom.scss

@@ -105,6 +105,13 @@ body {
   margin-bottom: auto;
 }
 
+#contribute .feature__item {
+  @media (min-width: 37.5em) {
+    width: 45%;
+    margin-inline-start: 3.3%;
+  }
+}
+
 #blog {
   margin-top: 2em;
   background-color: #eee;

src/index.html

@@ -36,9 +36,12 @@ documentation_list:
       <li><a href="https://tahoe-lafs.org/trac/tahoe-lafs/wiki/Doc">Index of docs</a></li>
       <li><a href="https://tahoe-lafs.org/trac/tahoe-lafs/wiki/FAQ">Frequently Asked Questions</a></li>
     </ul>'
-contribute:
+get-involved:
-  - title: "Contribute"
+  - title: "Get Involved"
-    excerpt: ""
+    excerpt: '
+      Interested in learning more or wanting to contribute to Tahoe-LAFS?<br/>
+      There are various ways to get involved!
+    '
 contribute_list:
   - image_path: /assets/images/discussions.svg
     alt: "discussions"
@@ -46,8 +49,15 @@ contribute_list:
     excerpt: '<ul>
       <li>Join <a href="https://lists.tahoe-lafs.org/mailman/listinfo/tahoe-dev" target="_blank">the <b>tahoe-dev</b></a> mailing list</li>
       <li>Join the <a href="https://libera.chat/" target="_blank"><b>#tahoe-lafs</b></a> channel on Libera</li>
-      <li>Meet us on <a href="https://meet.jit.si/AccurateFiltersManipulateBefore" target="blank"><b>Tuesday</b></a> at 17:00 UTC on Jitsi </li>
+      <li>Meet us on <a href="https://meet.jit.si/AccurateFiltersManipulateBefore" target="_blank"><b>Tuesday</b></a> at 17:00 UTC on Jitsi </li>
     </ul>'
+  - image_path: /assets/images/volunteers.svg
+    alt: "volunteers"
+    title: "Volunteers"
+    excerpt: '
+      Tahoe-LAFS is an open-source project supported by donations and maintained by a group of hardy
+      <a href="https://tahoe-lafs.org/trac/tahoe-lafs/wiki/AboutUs" target="_blank">volunteers</a>.
+    '
   - image_path: /assets/images/issues.svg
     alt: "issues"
     title: "Issues"
@@ -80,8 +90,10 @@ about:
 {% include feature_row id="documentation_list" %}
 </div>
 
+<div id="get-involved">
+{% include feature_row id="get-involved" type="center" %}
+</div>
 <div id="contribute">
-{% include feature_row id="contribute" type="center" %}
 {% include feature_row id="contribute_list" %}
 </div>