Update critical file(s) according to Chirpy v6.3.1

Gemfile

@@ -2,7 +2,7 @@
 
 source "https://rubygems.org"
 
-gem "jekyll-theme-chirpy", "~> 6.2", ">= 6.2.3"
+gem "jekyll-theme-chirpy", "~> 6.3", ">= 6.3.1"
 
 group :test do
   gem "html-proofer", "~> 4.4"

_data/share.yml

@@ -23,3 +23,16 @@ platforms:
   # - type: Weibo
   #   icon: "fab fa-weibo"
   #   link: "http://service.weibo.com/share/share.php?title=TITLE&url=URL"
+  #
+  # - type: Mastodon
+  #   icon: "fa-brands fa-mastodon"
+  #   # See: https://github.com/justinribeiro/share-to-mastodon#properties
+  #   instances:
+  #     - label: mastodon.social
+  #       link: "https://mastodon.social/"
+  #     - label: mastodon.online
+  #       link: "https://mastodon.online/"
+  #     - label: fosstodon.org
+  #       link: "https://fosstodon.org/"
+  #     - label: photog.social
+  #       link: "https://photog.social/"