deps: Lock concurrent-ruby v1.3.4

related. #2533

Author: toshimaru

Gemfile

@@ -48,3 +48,4 @@ end
 
 gem "net-imap", "~> 0.4.19"
 gem "zeitwerk", "~> 2.6.0"
+gem "concurrent-ruby", "1.3.4"

Gemfile.lock

@@ -90,7 +90,7 @@ GEM
       xpath (~> 3.2)
     code-scanning-rubocop (0.6.1)
       rubocop (~> 1.0)
-    concurrent-ruby (1.3.5)
+    concurrent-ruby (1.3.4)
     crass (1.0.6)
     date (3.4.1)
     debug (1.10.0)
@@ -345,6 +345,7 @@ DEPENDENCIES
   bullet
   capybara
   code-scanning-rubocop
+  concurrent-ruby (= 1.3.4)
   debug
   factory_bot_rails
   faker