Ruby 3.0

[denny]

• Bump Ruby to 3.0.1

• Bump gems as required

• Add monkey-patch for URL.escape (deprecated in Ruby 3.x but still used by paperclip gem)

• Add note re. deprecation of paperclip gem.

[codecov]

Codecov Report

Merging #256 (ad92642) into main (8ee48c7) will increase coverage by 0.75%.
The diff coverage is 100.00%.

❗ Current head ad92642 differs from pull request most recent head c034c2f. Consider uploading reports for the commit c034c2f to get more accurate results

@@             Coverage Diff             @@
##             main      #256      +/-   ##
===========================================
+ Coverage   99.24%   100.00%   +0.75%     
===========================================
  Files          24        25       +1     
  Lines         133       138       +5     
===========================================
+ Hits          132       138       +6     
+ Misses          1         0       -1     

Impacted Files	Coverage Δ
config/initializers/paperclip_url_escape_fix.rb	100.00% <100.00%> (ø)
app/controllers/sessions_controller.rb	100.00% <0.00%> (+10.00%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8ee48c7...c034c2f. Read the comment docs.