diff --git a/Gemfile b/Gemfile
index ce42cac..4027434 100644
--- a/Gemfile
+++ b/Gemfile
@@ -23,7 +23,7 @@ end
 
 lockfile "ruby-2.6", active: RUBY_VERSION < "2.7" do
   # newer versions of these gems are not compatible with Ruby > 2.6
-  gem "debug", "1.8.0", require: false
+  gem "debug", "~> 1.8.0", require: false
   gem "irb", "1.6.3", require: false
-  gem "stringio", "3.0.6", require: false
+  gem "stringio", "~> 3.0.6", require: false
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index bb47f75..27c65ec 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -12,7 +12,7 @@ GEM
     debug (1.9.0)
       irb (~> 1.10)
       reline (>= 0.3.8)
-    diff-lcs (1.5.0)
+    diff-lcs (1.5.1)
     gem-release (2.2.2)
     io-console (0.7.2)
     irb (1.11.0)
@@ -28,26 +28,26 @@ GEM
       stringio
     racc (1.7.1)
     rainbow (3.1.1)
-    rake (13.0.6)
+    rake (13.1.0)
     rdoc (6.6.2)
       psych (>= 4.0.0)
     regexp_parser (2.8.1)
     reline (0.4.2)
       io-console (~> 0.5)
     rexml (3.2.6)
-    rspec (3.12.0)
-      rspec-core (~> 3.12.0)
-      rspec-expectations (~> 3.12.0)
-      rspec-mocks (~> 3.12.0)
-    rspec-core (3.12.2)
-      rspec-support (~> 3.12.0)
-    rspec-expectations (3.12.3)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-mocks (3.12.6)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-support (3.12.1)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
     rubocop (1.56.3)
       base64 (~> 0.1.1)
       json (~> 2.3)
diff --git a/Gemfile.ruby-2.6.lock b/Gemfile.ruby-2.6.lock
index b0085e5..173cee1 100644
--- a/Gemfile.ruby-2.6.lock
+++ b/Gemfile.ruby-2.6.lock
@@ -10,28 +10,28 @@ GEM
     debug (1.8.0)
       irb (>= 1.5.0)
       reline (>= 0.3.1)
-    diff-lcs (1.5.0)
+    diff-lcs (1.5.1)
     gem-release (2.2.2)
     io-console (0.7.2)
     irb (1.6.3)
       reline (>= 0.3.0)
-    rake (13.0.6)
+    rake (13.1.0)
     reline (0.4.2)
       io-console (~> 0.5)
-    rspec (3.12.0)
-      rspec-core (~> 3.12.0)
-      rspec-expectations (~> 3.12.0)
-      rspec-mocks (~> 3.12.0)
-    rspec-core (3.12.2)
-      rspec-support (~> 3.12.0)
-    rspec-expectations (3.12.3)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-mocks (3.12.6)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-support (3.12.1)
-    stringio (3.0.6)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    stringio (3.0.9)
 
 PLATFORMS
   aarch64-linux
@@ -42,12 +42,12 @@ PLATFORMS
 
 DEPENDENCIES
   bundler-multilock!
-  debug (= 1.8.0)
+  debug (~> 1.8.0)
   gem-release (~> 2.2)
   irb (= 1.6.3)
   rake (~> 13.0)
   rspec (~> 3.12)
-  stringio (= 3.0.6)
+  stringio (~> 3.0.6)
 
 BUNDLED WITH
    2.5.6