Merge pull request #85 from commonlit/gh-regex-match

Use Regexp#match? over String#=~ when testing for null bytes

lib/rack/utf8_sanitizer.rb

@@ -49,7 +49,7 @@ def call(env)
         input.
           force_encoding(Encoding::ASCII_8BIT).
           encode!(Encoding::UTF_8)
-        if sanitize_null_bytes && input =~ NULL_BYTE_REGEX
+        if sanitize_null_bytes && NULL_BYTE_REGEX.match?(input)
           raise NullByteInString
         end
         input