Bump dotenv-rails from 2.7.6 to 2.8.1

Bumps [dotenv-rails](https://github.com/bkeepers/dotenv) from 2.7.6 to 2.8.1.
- [Release notes](https://github.com/bkeepers/dotenv/releases)
- [Changelog](https://github.com/bkeepers/dotenv/blob/master/Changelog.md)
- [Commits](https://github.com/bkeepers/dotenv/compare/v2.7.6...v2.8.1)

---
updated-dependencies:
- dependency-name: dotenv-rails
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -201,9 +201,9 @@ GEM
     discard (1.2.1)
       activerecord (>= 4.2, < 8)
     docile (1.1.5)
-    dotenv (2.7.6)
-    dotenv-rails (2.7.6)
-      dotenv (= 2.7.6)
+    dotenv (2.8.1)
+    dotenv-rails (2.8.1)
+      dotenv (= 2.8.1)
       railties (>= 3.2)
     elasticsearch (6.8.3)
       elasticsearch-api (= 6.8.3)
@@ -387,7 +387,7 @@ GEM
     multi_xml (0.6.0)
     multipart-post (2.1.1)
     nio4r (2.5.8)
-    nokogiri (1.13.7)
+    nokogiri (1.13.8)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     oauth (0.5.6)
@@ -609,7 +609,7 @@ GEM
     tilt (2.0.10)
     timecop (0.9.5)
     trollop (1.16.2)
-    tzinfo (2.0.4)
+    tzinfo (2.0.5)
       concurrent-ruby (~> 1.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)