Update reverse_markdown requirement from ~> 2.1 to >= 2.1, < 4.0

Updates the requirements on [reverse_markdown](https://github.com/xijo/reverse_markdown) to permit the latest version.
- [Changelog](https://github.com/xijo/reverse_markdown/blob/master/CHANGELOG.md)
- [Commits](xijo/reverse_markdown@v2.1.1...v3.0.0)

---
updated-dependencies:
- dependency-name: reverse_markdown
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -6,7 +6,7 @@ PATH
       licensee (~> 9.16)
       parallel (~> 1.22)
       pathname-common_prefix (~> 0.0.1)
-      reverse_markdown (~> 2.1)
+      reverse_markdown (>= 2.1, < 4.0)
       ruby-xxHash (~> 0.4.0)
       thor (~> 1.2)
       tomlrb (~> 2.0)
@@ -41,21 +41,21 @@ GEM
     i18n (1.14.4)
       concurrent-ruby (~> 1.0)
     json (2.7.2)
-    licensee (9.16.0)
-      dotenv (~> 2.0)
-      octokit (>= 4.20, < 7.0)
-      reverse_markdown (>= 1, < 3)
+    licensee (9.18.0)
+      dotenv (>= 2, < 4)
+      octokit (>= 4.20, < 10.0)
+      reverse_markdown (>= 1, < 4)
       rugged (>= 0.24, < 2.0)
       thor (>= 0.19, < 2.0)
-    mini_portile2 (2.8.1)
+    mini_portile2 (2.8.8)
     minitest (5.25.1)
     minitest-hooks (1.5.2)
       minitest (> 5.3)
     mocha (2.4.5)
       ruby2_keywords (>= 0.0.5)
     mutex_m (0.2.0)
-    nokogiri (1.16.5)
-      mini_portile2 (~> 2.8.0)
+    nokogiri (1.16.7)
+      mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     octokit (6.1.0)
       faraday (>= 1, < 3)
@@ -65,12 +65,12 @@ GEM
       ast (~> 2.4.1)
     pathname-common_prefix (0.0.2)
     public_suffix (5.0.1)
-    racc (1.6.2)
+    racc (1.8.1)
     rack (3.0.9.1)
     rainbow (3.1.1)
     rake (13.2.1)
     regexp_parser (2.6.2)
-    reverse_markdown (2.1.1)
+    reverse_markdown (3.0.0)
       nokogiri
     rexml (3.3.9)
     rubocop (1.45.1)

licensed.gemspec

@@ -29,7 +29,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "tomlrb", "~> 2.0"
   spec.add_dependency "ruby-xxHash", "~> 0.4.0"
   spec.add_dependency "parallel", "~> 1.22"
-  spec.add_dependency "reverse_markdown", "~> 2.1"
+  spec.add_dependency "reverse_markdown", ">= 2.1", "< 4.0"
   spec.add_dependency "json", "~> 2.6"
 
   spec.add_development_dependency "rake", "~> 13.0"