Bump letter_opener from 1.6.0 to 1.7.0 (#9493)

Bumps [letter_opener](https://github.com/ryanb/letter_opener) from 1.6.0 to 1.7.0.
- [Release notes](https://github.com/ryanb/letter_opener/releases)
- [Changelog](https://github.com/ryanb/letter_opener/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ryanb/letter_opener/compare/v1.6.0...v1.7.0)

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

Gemfile

@@ -124,7 +124,7 @@ group :development do
   gem 'better_errors', '~> 2.5'
   gem 'binding_of_caller', '~> 0.7'
   gem 'bullet', '~> 5.9'
-  gem 'letter_opener', '~> 1.4'
+  gem 'letter_opener', '~> 1.7'
   gem 'letter_opener_web', '~> 1.3'
   gem 'memory_profiler'
   gem 'rubocop', '~> 0.61', require: false

Gemfile.lock

@@ -310,7 +310,7 @@ GEM
     kaminari-core (1.1.1)
     launchy (2.4.3)
       addressable (~> 2.3)
-    letter_opener (1.6.0)
+    letter_opener (1.7.0)
       launchy (~> 2.2)
     letter_opener_web (1.3.4)
       actionmailer (>= 3.2)
@@ -699,7 +699,7 @@ DEPENDENCIES
   json-ld (~> 2.2)
   json-ld-preloaded (~> 3.0)
   kaminari (~> 1.1)
-  letter_opener (~> 1.4)
+  letter_opener (~> 1.7)
   letter_opener_web (~> 1.3)
   link_header (~> 0.0)
   lograge (~> 0.10)