add matrix needed by prawn

Gemfile

@@ -55,6 +55,7 @@ gem 'listen' # Required by ActiveSupport::EventedFileUpdateChecker
 gem 'lograge'
 gem 'logstash-event'
 gem 'mailjet', require: false
+gem 'matrix' # needed by prawn and not default in ruby 3.1
 gem 'net-smtp', require: false # See https://github.com/mikel/mail/pull/1439
 gem 'openid_connect'
 gem 'pg'

Gemfile.lock

@@ -355,7 +355,7 @@ GEM
       ruby-vips (>= 2.0.17, < 3)
     invisible_captcha (2.0.0)
       rails (>= 5.0)
-    io-wait (0.2.0)
+    io-wait (0.2.1)
     ipaddress (0.8.3)
     jquery-rails (4.4.0)
       rails-dom-testing (>= 1, < 3)
@@ -412,6 +412,7 @@ GEM
       rack (>= 1.4.0)
       rest-client (>= 2.0.0)
     marcel (1.0.2)
+    matrix (0.4.2)
     method_source (1.0.0)
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
@@ -842,6 +843,7 @@ DEPENDENCIES
   lograge
   logstash-event
   mailjet
+  matrix
   mina
   net-smtp
   openid_connect