minor #18996 Redis change default branch and docs location (snebes)

This PR was merged into the 5.4 branch.

Discussion
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Redis change default branch and docs location

the php-redis repo changed the default branch name away from master and restructured the documentation.  These are the new updated links.

This could go all the way back to symfony 3.3 docs, but put a PR against 5.4 as it is still maintained.

Commits
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95dc3ea Redis change default branch and docs location

Author: OskarStark

components/cache/adapters/redis_adapter.rst

@@ -250,8 +250,8 @@ Read more about this topic in the official `Redis LRU Cache Documentation`_.
 .. _`Data Source Name (DSN)`: https://en.wikipedia.org/wiki/Data_source_name
 .. _`Redis server`: https://redis.io/
 .. _`Redis`: https://github.com/phpredis/phpredis
-.. _`RedisArray`: https://github.com/phpredis/phpredis/blob/master/arrays.markdown#readme
-.. _`RedisCluster`: https://github.com/phpredis/phpredis/blob/master/cluster.markdown#readme
+.. _`RedisArray`: https://github.com/phpredis/phpredis/blob/develop/arrays.md
+.. _`RedisCluster`: https://github.com/phpredis/phpredis/blob/develop/cluster.md
 .. _`Predis`: https://packagist.org/packages/predis/predis
 .. _`Predis Connection Parameters`: https://github.com/nrk/predis/wiki/Connection-Parameters#list-of-connection-parameters
 .. _`TCP-keepalive`: https://redis.io/topics/clients#tcp-keepalive