bump to v3.15.11

[CollinBeczak]

What's Changed

• Fix Rapid editor iframe changeset comment formatting (hotfix) by @jake-low in Fix Rapid editor iframe changeset comment formatting (hotfix) #2435
• Pin Rapid editor version to 2.3 via jsDelivr CDN URL by @jake-low in Pin Rapid editor version to 2.3 via jsDelivr CDN URL #2436
• Properly pin Rapid editor to 2.3 by @jake-low in Properly pin Rapid editor to 2.3 #2437
• allow 'not an issue' status change for revisions by @CollinBeczak in allow 'not an issue' status change for revisions #2439
• fix feature animation and hover styles by @CollinBeczak in fix feature animation and hover styles #2440
• Profile: Add dom id to api key section by @jake-low in Profile: Add dom id to api key section #2448
• Update caniuse-lite db by @jake-low in Update caniuse-lite db #2443
• Prevent codecov from polluting PRs with useless comments by @jake-low in Prevent codecov from polluting PRs with useless comments #2445
• Run svgo on static svgs to reduce file size by @jake-low in Run svgo on static svgs to reduce file size #2442
• Improve error messages when Rapid editor fails to load by @jake-low in Improve error messages when Rapid editor fails to load #2441
• fix infinite loading screen on challenge browse page by @CollinBeczak in fix infinite loading screen on challenge browse page #2456
• fix challenge completion indicator by @CollinBeczak in fix challenge completion indicator #2457
• Enable Challenge and Project leaderboards by @jschwarz2030 in Enable Challenge and Project leaderboards #2461
• Bump Rapid to 2.4.2 by @jake-low in Bump rapid editor version to 2.4.2 #2464

MR2 Changes

• Add challenge and project leaderboard endpoints by @jschwarz2030 in add challenge and project leaderboard endpoints maproulette-backend#1152
• Add link to OSM US Code of Conduct by @jake-low in Add link to OSM US Code of Conduct maproulette-backend#1151
• Fix remaining task total in challenges by @CollinBeczak in fix remaining task total in challenges maproulette-backend#1150
• Swagger: How to get the API Key; Other notes by @tordans in Swagger: How to get the API Key and other notes maproulette-backend#1149

Released with maproulette-backend_v4.5.6
Full Changelog: v3.15.10...v3.15.11