Bump Redis version to 8.2.1

[adamiBs]

This PR bumps the Redis version from 8.2.1-int to the official Redis 8.2.1 release.

Changes

• Update REDIS_DOWNLOAD_URL to use the official Redis 8.2.1 release tarball from http://download.redis.io/releases/redis-8.2.1.tar.gz
• Update REDIS_DOWNLOAD_SHA to the correct SHA256 hash: e2c1cb9dd4180a35b943b85dfc7dcdd42566cdbceca37d0d0b14c21731582d3e
• Switch from internal 8.2.1-int tag to official 8.2.1 release

Files Modified

• alpine/Dockerfile
• debian/Dockerfile

Verification

The SHA256 hash was verified by downloading the tarball directly:

curl -s http://download.redis.io/releases/redis-8.2.1.tar.gz | sha256sum
# e2c1cb9dd4180a35b943b85dfc7dcdd42566cdbceca37d0d0b14c21731582d3e

Release Information

This change aligns the Docker images with the official Redis 8.2.1 release:

• Release Date: August 18, 2025
• Commit SHA: cd0b129
• Release Notes: https://github.com/redis/redis/releases/tag/8.2.1

Bug Fixes in 8.2.1

• #14240 INFO KEYSIZES - potential incorrect histogram updates on cluster mode with modules
• #14274 Disable Active Defrag during flushing replica
• #14276 XADD or XTRIM can crash the server after loading RDB
• #Q6601 Potential crash when running FLUSHDB (MOD-10681)

Performance and Resource Utilization

• Query Engine - LeanVec and LVQ proprietary Intel optimizations were removed from Redis Open Source
• #Q6621 Fix regression in INFO (MOD-10779)

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Pull Request opened by Augment Code with guidance from the PR author