Bump pghero from 2.8.1 to 3.1.0

Bumps [pghero](https://github.com/ankane/pghero) from 2.8.1 to 3.1.0.
- [Release notes](https://github.com/ankane/pghero/releases)
- [Changelog](https://github.com/ankane/pghero/blob/master/CHANGELOG.md)
- [Commits](ankane/pghero@v2.8.1...v3.1.0)

---
updated-dependencies:
- dependency-name: pghero
  dependency-type: direct:production
...

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

Gemfile

@@ -14,7 +14,7 @@ gem 'rack', '~> 2.2.6'
 gem 'hamlit-rails', '~> 0.2'
 gem 'pg', '~> 1.2'
 gem 'makara', '~> 0.5'
-gem 'pghero', '~> 2.8'
+gem 'pghero', '~> 3.1'
 gem 'dotenv-rails', '~> 2.7'
 
 gem 'aws-sdk-s3', '~> 1.102', require: false

Gemfile.lock

@@ -289,7 +289,7 @@ GEM
     httplog (1.5.0)
       rack (>= 1.0)
       rainbow (>= 2.0.0)
-    i18n (1.8.10)
+    i18n (1.12.0)
       concurrent-ruby (~> 1.0)
     i18n-tasks (0.9.34)
       activesupport (>= 4.0.2)
@@ -375,7 +375,7 @@ GEM
       rake
     mini_mime (1.1.1)
     mini_portile2 (2.8.1)
-    minitest (5.14.4)
+    minitest (5.17.0)
     msgpack (1.4.2)
     multi_json (1.15.0)
     multipart-post (2.1.1)
@@ -435,8 +435,8 @@ GEM
     pastel (0.8.0)
       tty-color (~> 0.5)
     pg (1.2.3)
-    pghero (2.8.1)
-      activerecord (>= 5)
+    pghero (3.1.0)
+      activerecord (>= 6)
     pkg-config (1.4.6)
     posix-spawn (0.3.15)
     premailer (1.14.2)
@@ -664,7 +664,7 @@ GEM
     twitter-text (3.1.0)
       idn-ruby
       unf (~> 0.1.0)
-    tzinfo (2.0.4)
+    tzinfo (2.0.5)
       concurrent-ruby (~> 1.0)
     tzinfo-data (1.2021.1)
       tzinfo (>= 1.0.0)
@@ -713,7 +713,7 @@ GEM
     xorcist (1.1.2)
     xpath (3.2.0)
       nokogiri (~> 1.8)
-    zeitwerk (2.4.2)
+    zeitwerk (2.6.6)
 
 PLATFORMS
   ruby
@@ -797,7 +797,7 @@ DEPENDENCIES
   parallel_tests (~> 3.7)
   parslet
   pg (~> 1.2)
-  pghero (~> 2.8)
+  pghero (~> 3.1)
   pkg-config (~> 1.4)
   posix-spawn
   premailer-rails