Bump Nokogiri to 1.13.3, previous version don't support Ruby 3.1:

- I was trying to work on Rails using Ruby 3.1 but the locked
  bundler dependencies didn't resolve. The previously locked
  version of Nokogiri (v1.12.5) has a constraint on Ruby
  `[">= 2.5".freeze, "< 3.1.dev".freeze]`.

  Things works correctly on CI now because the Gemfile.lock get
  deleted https://github.com/rails/buildkite-config/blob/ed61405b4b52f480a49e3556ccc50ce0dcbda31d/Dockerfile#L134

  Bumping to 1.13.3 as that's what CI uses anyway

Author: Edouard-chin

Gemfile.lock

@@ -331,7 +331,7 @@ GEM
     method_source (1.0.0)
     mini_magick (4.11.0)
     mini_mime (1.1.2)
-    mini_portile2 (2.6.1)
+    mini_portile2 (2.8.0)
     minitest (5.15.0)
     minitest-bisect (1.5.1)
       minitest-server (~> 1.0)
@@ -367,12 +367,12 @@ GEM
       net-protocol
       timeout
     nio4r (2.5.8)
-    nokogiri (1.12.5)
-      mini_portile2 (~> 2.6.1)
+    nokogiri (1.13.3)
+      mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
-    nokogiri (1.12.5-x86_64-darwin)
+    nokogiri (1.13.3-x86_64-darwin)
       racc (~> 1.4)
-    nokogiri (1.12.5-x86_64-linux)
+    nokogiri (1.13.3-x86_64-linux)
       racc (~> 1.4)
     os (1.1.4)
     parallel (1.21.0)