Bump nokogiri from 1.10.4 to 1.13.4

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.4 to 1.13.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/v1.13.4/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.10.4...v1.13.4)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -1,5 +1,5 @@
 GIT
-  remote: git://github.com/transitland/gtfs.git
+  remote: https://github.com/transitland/gtfs.git
   revision: 35ece1267514479b8785fe644cc69dddbb25f758
   tag: 35ece1267514479b8785fe644cc69dddbb25f758
   specs:
@@ -891,13 +891,14 @@ GEM
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
     mini_mime (1.0.1)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.0)
     minitest (5.12.2)
     multi_json (1.13.1)
     multipart-post (2.0.0)
     netrc (0.11.0)
-    nokogiri (1.10.4)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.13.4)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     oj (3.7.9)
     orm_adapter (0.5.0)
     pg (0.21.0)
@@ -921,6 +922,7 @@ GEM
       pry (>= 0.9.11)
     public_suffix (3.0.3)
     puma (3.12.0)
+    racc (1.6.0)
     rack (1.6.11)
     rack-cors (1.0.6)
       rack (>= 1.6.0)