Update webrick to version 1.9.1

Author: depfu[bot]

Gemfile.lock

@@ -12,6 +12,7 @@ GEM
     backports (3.25.0)
     byebug (11.1.3)
     commonmarker (1.1.5-arm64-darwin)
+    commonmarker (1.1.5-x86_64-linux)
     diff-lcs (1.5.1)
     diffy (3.4.2)
     docile (1.4.1)
@@ -129,7 +130,7 @@ GEM
     unicode-display_width (2.6.0)
     uri (0.13.1)
     version_gem (1.1.4)
-    webrick (1.8.2)
+    webrick (1.9.1)
     yard (0.9.37)
     yard-junk (0.0.10)
       backports (>= 3.18)