Revert #213 and only upgrade a few dependencies (and not Rails)

Gemfile

@@ -21,7 +21,9 @@ gem 'rack-canonical-host', '1.3.0'
 gem 'rack-cors', require: 'rack/cors'
 gem 'rack-ssl', require: 'rack/ssl'
 gem 'rails', '6.1.7.7'
+gem 'rails-html-sanitizer', '~> 1.6'
 gem 'ranked-model'
+gem 'rexml', '~> 3.3'
 gem 'sass-rails', '~> 5.1'
 gem 'sentry-rails'
 gem 'sentry-ruby'

Gemfile.lock

@@ -72,7 +72,6 @@ GEM
     babel-transpiler (0.7.0)
       babel-source (>= 4.0, < 6)
       execjs (~> 2.0)
-    base64 (0.2.0)
     bcrypt (3.1.19)
     bigdecimal (3.1.7)
     blockenspiel (0.5.0)
@@ -83,21 +82,21 @@ GEM
       activemodel (>= 3.0.0)
     brakeman (6.1.2)
       racc
-    builder (3.3.0)
+    builder (3.2.4)
     bundler-audit (0.9.1)
       bundler (>= 1.2.0, < 3)
       thor (~> 1.0)
     camaraderie (0.2.1)
       activerecord (>= 3.0.0)
       activesupport (>= 3.0.0)
     cancancan (3.5.0)
-    concurrent-ruby (1.3.4)
+    concurrent-ruby (1.2.3)
     crass (1.0.6)
     database_cleaner-active_record (2.1.0)
       activerecord (>= 5.a)
       database_cleaner-core (~> 2.0.0)
     database_cleaner-core (2.0.1)
-    date (3.4.1)
+    date (3.3.4)
     devise (4.9.3)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
@@ -107,7 +106,7 @@ GEM
     diff-lcs (1.5.1)
     ecma-re-validator (0.4.0)
       regexp_parser (~> 2.2)
-    erubi (1.13.1)
+    erubi (1.12.0)
     execjs (2.8.1)
     factory_bot (6.4.5)
       activesupport (>= 5.0.0)
@@ -122,7 +121,7 @@ GEM
     globalid (1.2.1)
       activesupport (>= 6.1)
     hana (1.3.7)
-    i18n (1.14.6)
+    i18n (1.14.4)
       concurrent-ruby (~> 1.0)
     jquery-turbolinks (2.1.0)
       railties (>= 3.1.0)
@@ -143,22 +142,22 @@ GEM
       net-imap
       net-pop
       net-smtp
-    marcel (1.0.4)
-    method_source (1.1.0)
+    marcel (1.0.2)
+    method_source (1.0.0)
     mini_check (0.3.0)
       json
     mini_mime (1.1.5)
     mini_portile2 (2.8.8)
-    minitest (5.25.4)
+    minitest (5.22.3)
     msgpack (1.7.2)
-    net-imap (0.5.5)
+    net-imap (0.4.10)
       date
       net-protocol
     net-pop (0.1.2)
       net-protocol
     net-protocol (0.2.2)
       timeout
-    net-smtp (0.5.0)
+    net-smtp (0.4.0.1)
       net-protocol
     nio4r (2.7.4)
     nokogiri (1.18.1)
@@ -177,7 +176,7 @@ GEM
     puma (6.5.0)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (2.2.10)
+    rack (2.2.9)
     rack-accept (0.4.5)
       rack (>= 0.4)
     rack-canonical-host (1.3.0)
@@ -187,7 +186,7 @@ GEM
       rack (>= 2.0.0)
     rack-ssl (1.4.1)
       rack
-    rack-test (2.2.0)
+    rack-test (2.1.0)
       rack (>= 1.3)
     rails (6.1.7.7)
       actioncable (= 6.1.7.7)
@@ -223,7 +222,7 @@ GEM
       rake (>= 12.2)
       thor (~> 1.0)
     rainbow (3.1.1)
-    rake (13.2.1)
+    rake (13.1.0)
     ranked-model (0.4.9)
       activerecord (>= 5.2)
     regexp_parser (2.9.0)
@@ -287,21 +286,20 @@ GEM
     spring (4.1.3)
     spring-commands-rspec (1.0.4)
       spring (>= 0.9.1)
-    sprockets (3.7.5)
-      base64
+    sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-es6 (0.9.2)
       babel-source (>= 5.8.11)
       babel-transpiler
       sprockets (>= 3.0.0)
-    sprockets-rails (3.5.2)
-      actionpack (>= 6.1)
-      activesupport (>= 6.1)
+    sprockets-rails (3.4.2)
+      actionpack (>= 5.2)
+      activesupport (>= 5.2)
       sprockets (>= 3.0.0)
-    thor (1.3.2)
+    thor (1.3.1)
     tilt (2.0.10)
-    timeout (0.4.3)
+    timeout (0.4.1)
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
@@ -318,11 +316,10 @@ GEM
       blockenspiel (~> 0.5)
     warden (1.2.9)
       rack (>= 2.0.9)
-    websocket-driver (0.7.7)
-      base64
+    websocket-driver (0.7.6)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
-    zeitwerk (2.7.1)
+    zeitwerk (2.6.13)
 
 PLATFORMS
   ruby
@@ -353,8 +350,10 @@ DEPENDENCIES
   rack-cors
   rack-ssl
   rails (= 6.1.7.7)
+  rails-html-sanitizer (~> 1.6)
   rails_12factor
   ranked-model
+  rexml (~> 3.3)
   rspec-rails (~> 6.1)
   rubocop (~> 1.62)
   rubocop-rails