Bump octicons from 19.11.0 to 19.12.0 in /demo (#3165)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

demo/Gemfile.lock

@@ -241,7 +241,7 @@ GEM
       racc (~> 1.4)
     nokogiri (1.16.7-x86_64-linux)
       racc (~> 1.4)
-    octicons (19.11.0)
+    octicons (19.12.0)
     oj (3.16.3)
       bigdecimal (>= 3.0)
     os (1.1.4)