chore(deps): bump next from 15.5.20 to 15.5.21

[dependabot]

Bumps next from 15.5.20 to 15.5.21.

Release notes

Sourced from next's releases.

v15.5.21

This release contains security fixes for the following advisories:

High:

• Denial of Service in App Router using Server Actions
• Middleware / Proxy bypass in App Router applications using Turbopack and single locale
• Server-Side Request Forgery in rewrites via attacker-controlled destination hostname
• Server-Side Request Forgery in Server Actions on custom servers

Moderate:

• Cache confusion of response bodies for requests with bodies
• Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences
• Denial of Service in the Image Optimization API using SVGs
• Unauthenticated disclosure of internal Server Function endpoints
• Unbounded Server Action payload in Edge runtime

Commits

• e26f6ff v15.5.21
• 7f5deeb [15.x] Improve performance of checking valid MPA form submissions
• 57c31f7 [15.x] Enforce serverActions.bodySizeLimit for Server Actions in Edge runtime
• e3e5666 [15.x] Set correct origin for internal redirects in custom server
• 35f5013 [15.x] Ensure exotic rewrite param values are properly encoded
• 062f667 [15.x] fix(fetch-cache): key fetch(Request, init) by the effective request
• 577c9dc [15.x] fix(incremental-cache): byte-exact fetch cache key for binary bodies
• 530d4fa [15.x] fix(next/image): improve performance of detectContentType()
• 8fabaf3 [15.x] Performance improvements when decoding React Server function payloads
• ff12a61 [15.x] Validate server reference IDs during manifest lookup
• Additional commits viewable in compare view