Supress warnings in Paperclip::UrlGenerator

We were getting hundreds of "warning: URI.escape is obsolete" messages.
So we're using `URI::DEFAULT_PARSER.escape` instead.

IMHO it's OK to add this monkey-patch because we're replacing Paperclip
with Active Storage, and when we finish with that we'll delete this
file.

config/initializers/paperclip.rb

@@ -0,0 +1,13 @@
+class Paperclip::UrlGenerator
+ private
+
+ # Code copied from the paperclip gem, only replacing
+ # `URI.escape` with `URI::DEFAULT_PARSER.escape`
+ def escape_url(url)
+ if url.respond_to?(:escape)
+ url.escape
+ else
+ URI::DEFAULT_PARSER.escape(url).gsub(escape_regex) { |m| "%#{m.ord.to_s(16).upcase}" }
+ end
+ end
+end