chore: bump to v2.6.0

[v0idpwn]

Features

• Authentication cleartext password support - Added support for cleartext password authentication method (feat: add authentication_cleartext_password support #707)
• Runtime-configurable connection retries - Support for runtime configuration of connection retries and infinite retries (feat: runtime-configurable connection retries. Support -1 for infinity #705)
• Enhanced health checks - Check database and eRPC capabilities during health check operations (feat: check database and erpc capabilities on health check #691)
• More consistency with postgres on auth errors - Improves errors in some client libraries (feat: more consistency with postgres errors on auth errors #711)

Performance Improvements

• Optimized ranch usage - Supavisor now uses a constant number of ranch instances for improved performance and resource management when hosting a large number of pools (perf: use a constant number of ranch instances #706)

Monitoring

• New OS memory metrics - gives a more accurate picture of memory usage (feat: better OS memory metrics #704)
• Add a promex plugin for cluster metrics - for tracking latency and connection status (feat: add cluster metrics promex plugin #690)
• Client connection lifetime metrics - adds a metric about how long each connection is connected for (feat: add metric for client connection lifetime #688)
• Process monitoring - Log when large process heaps and long message queues (feat: monitor large process heaps and long message queues #689)

Bug Fixes

• Client handler query cancellation - Fixed handling of :cancel_query when state is :idle (fix(client-handler): handle :cancel_query when state is :idle #692)

Migration Notes

• Instances running a small number of pools may see an increase in memory usage. This can be mitigated by changing the ranch shard or the acceptor counts.
• If using any of the new used ports, may need to change the defaults
• Review monitoring dashboards and include new metrics