Update slides for GitHub Codespaces support

Author: codebytes

.github/dependabot.yml

@@ -9,3 +9,7 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "weekly"
+  - package-ecosystem: "devcontainers" # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "weekly"

slides/Slides.md

@@ -168,6 +168,14 @@ p { text-align: center; }
 
 ---
 
+# GitHub Codespace templates
+
+[https://github.com/codespaces/templates](https://github.com/codespaces/templates)
+
+![bg right:60% width:95%](img/github-codespace-templates.png)
+
+---
+
 # DEMO TIME
 ![bg right 70%](img/connected-to-dev-container.png)