chore(deps): update dependency slather to v2.8.0 (#351)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Gemfile.lock

@@ -3,7 +3,7 @@ GEM
   specs:
     CFPropertyList (3.0.6)
       rexml
-    activesupport (7.1.1)
+    activesupport (7.1.2)
       base64
       bigdecimal
       concurrent-ruby (~> 1.0, >= 1.0.2)
@@ -19,7 +19,7 @@ GEM
       httpclient (~> 2.8, >= 2.8.3)
       json (>= 1.5.1)
     atomos (0.1.3)
-    base64 (0.1.1)
+    base64 (0.2.0)
     bigdecimal (3.1.4)
     claide (1.1.0)
     clamp (1.3.2)
@@ -63,7 +63,7 @@ GEM
     colored2 (3.1.2)
     concurrent-ruby (1.2.2)
     connection_pool (2.4.1)
-    drb (2.1.1)
+    drb (2.2.0)
       ruby2_keywords
     escape (0.0.4)
     ethon (0.16.0)
@@ -87,28 +87,28 @@ GEM
       xcinvoke (~> 0.3.0)
     json (2.6.3)
     liferaft (0.0.6)
-    mini_portile2 (2.8.4)
+    mini_portile2 (2.8.5)
     minitest (5.20.0)
     molinillo (0.8.0)
     mustache (1.1.1)
-    mutex_m (0.1.2)
+    mutex_m (0.2.0)
     nanaimo (0.3.0)
     nap (1.1.0)
     netrc (0.11.0)
-    nokogiri (1.14.5)
-      mini_portile2 (~> 2.8.0)
+    nokogiri (1.15.4)
+      mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     open4 (1.3.4)
     public_suffix (4.0.7)
-    racc (1.6.2)
+    racc (1.7.3)
     redcarpet (3.6.0)
     rexml (3.2.6)
     rouge (2.0.7)
     ruby-macho (2.5.1)
     ruby2_keywords (0.0.5)
     sassc (2.4.0)
       ffi (~> 1.9)
-    slather (2.7.5)
+    slather (2.8.0)
       CFPropertyList (>= 2.2, < 4)
       activesupport
       clamp (~> 1.3)