Update rake requirement from = 13.0.6 to = 13.1.0

Updates the requirements on [rake](https://github.com/ruby/rake) to permit the latest version.
- [Release notes](https://github.com/ruby/rake/releases)
- [Changelog](https://github.com/ruby/rake/blob/master/History.rdoc)
- [Commits](ruby/rake@v13.0.6...v13.1.0)

---
updated-dependencies:
- dependency-name: rake
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -100,7 +100,7 @@ GEM
       method_source (~> 1.0)
     racc (1.7.3)
     rainbow (3.0.0)
-    rake (13.0.6)
+    rake (13.1.0)
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
@@ -164,7 +164,7 @@ DEPENDENCIES
   guard (~> 2.18.1)
   guard-rspec (~> 4.7.3)
   pdf-inspector (~> 1.3.0)
-  rake (= 13.0.6)
+  rake (= 13.1.0)
   rspec (= 3.13.0)
   rubocop (~> 0.93.1)
   rubocop-performance (~> 1.10.2)

br_danfe.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'guard', '~> 2.18.1'
   spec.add_development_dependency 'guard-rspec', '~> 4.7.3'
   spec.add_development_dependency 'pdf-inspector', '~> 1.3.0'
-  spec.add_development_dependency 'rake', '13.0.6'
+  spec.add_development_dependency 'rake', '13.1.0'
   spec.add_development_dependency 'rspec', '3.13.0'
   spec.add_development_dependency 'rubocop', '~> 0.93.1'
   spec.add_development_dependency 'rubocop-performance', '~> 1.10.2'