docs: add slides

src/content/talk/communities-contribution.md

@@ -1,6 +1,12 @@
 ---
 title: Communities and contribution
 description: Why I mentor, why I've organised meetups and conferences, why I give talks, and why I maintain and contribute to open-source software.
+
+speakerdeck:
+  id: 63c2fcc2294641688f433d062282a968
+  ratio: "1.78343949044586"
+  url: https://speakerdeck.com/opdavies/building-and-presenting-slide-decks-with-rst2pdf
+
 events:
   - name: TechConnect London
     location: London, UK