Bump dotenv-rails from 2.6.0 to 2.8.1

Bumps [dotenv-rails](https://github.com/bkeepers/dotenv) from 2.6.0 to 2.8.1.
- [Release notes](https://github.com/bkeepers/dotenv/releases)
- [Changelog](https://github.com/bkeepers/dotenv/blob/master/Changelog.md)
- [Commits](bkeepers/dotenv@v2.6.0...v2.8.1)

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

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

Gemfile

@@ -17,7 +17,7 @@ gem 'newrelic_rpm'
 gem 'active_interaction', "~> 3.6"
 gem 'faraday-panoptes', "~> 0.3"
 gem 'panoptes-client', "~> 0.3"
-gem 'dotenv-rails', "~> 2.6"
+gem 'dotenv-rails', "~> 2.8"
 
 group :development, :test do
   gem 'byebug', "~> 10.0"

Gemfile.lock

@@ -78,10 +78,10 @@ GEM
     crass (1.0.6)
     database_cleaner (1.7.0)
     diff-lcs (1.3)
-    dotenv (2.6.0)
-    dotenv-rails (2.6.0)
-      dotenv (= 2.6.0)
-      railties (>= 3.2, < 6.0)
+    dotenv (2.8.1)
+    dotenv-rails (2.8.1)
+      dotenv (= 2.8.1)
+      railties (>= 3.2)
     erubi (1.10.0)
     factory_girl (4.9.0)
       activesupport (>= 3.0.0)
@@ -104,7 +104,7 @@ GEM
       activesupport (>= 5.0)
     hitimes (1.2.6)
     honeybadger (4.12.1)
-    i18n (1.11.0)
+    i18n (1.12.0)
       concurrent-ruby (~> 1.0)
     ice_cube (0.14.0)
     json (2.3.0)
@@ -128,7 +128,7 @@ GEM
       ruby2_keywords (~> 0.0.1)
     newrelic_rpm (4.7.1.340)
     nio4r (2.5.8)
-    nokogiri (1.13.7)
+    nokogiri (1.13.8)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     panoptes-client (0.3.8)
@@ -248,7 +248,7 @@ DEPENDENCIES
   active_model_serializers (~> 0.10)
   byebug (~> 10.0)
   database_cleaner (~> 1.7)
-  dotenv-rails (~> 2.6)
+  dotenv-rails (~> 2.8)
   factory_girl_rails (~> 4.8)
   faraday-detailed_logger (~> 2.5)
   faraday-panoptes (~> 0.3)