chore(deps): update plug_cowboy

[marandaneto]

💡 Motivation and Context

The compliance adapter and test dependency lockfiles pin plug_cowboy versions affected by CVE-2026-32688. The adapter currently uses plain HTTP, so the reported HTTPS and HTTP/2 attack is not exposed by its current configuration. Updating the dependency still prevents affected versions from being used if that configuration changes and removes the vulnerable lockfile entries.

Fixes #194.

💚 How did you test it?

• Ran mix format --check-formatted sdk_compliance_adapter/mix.exs.
• Ran MIX_ENV=test mix test --exclude integration: 407 tests passed and 18 integration tests were excluded.
• Ran mix test in sdk_compliance_adapter: the adapter compiled successfully and has no tests.
• Built the compliance adapter Docker image successfully. The build used the checked-in lockfile and resolved plug_cowboy 2.9.0.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran sampo add to generate a changeset file

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Pi coding agent investigated the advisory, updated the dependency requirement and lockfiles, and made the Docker build use the adapter lockfile. Pi autoreview checked the final commit and reported no actionable findings.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "chore(deps): update plug_cowboy" | Re-trigger Greptile}

[github-actions]

posthog-elixir Compliance Report

Date: 2026-08-27 10:15:45 UTC
Duration: 117655ms

✅ All Tests Passed!

46/46 tests passed

---

Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	609ms
Format Validation.Event Has Uuid	✅	608ms
Format Validation.Event Has Lib Properties	✅	610ms
Format Validation.Distinct Id Is String	✅	609ms
Format Validation.Token Is Present	✅	610ms
Format Validation.Custom Properties Preserved	✅	609ms
Format Validation.Event Has Timestamp	✅	608ms
Retry Behavior.Retries On 503	✅	5613ms
Retry Behavior.Does Not Retry On 400	✅	2613ms
Retry Behavior.Does Not Retry On 401	✅	2613ms
Retry Behavior.Respects Retry After Header	✅	5616ms
Retry Behavior.Implements Backoff	✅	15626ms
Retry Behavior.Retries On 500	✅	5616ms
Retry Behavior.Retries On 502	✅	5616ms
Retry Behavior.Retries On 504	✅	5615ms
Retry Behavior.Max Retries Respected	✅	15626ms
Deduplication.Generates Unique Uuids	✅	621ms
Deduplication.Preserves Uuid On Retry	✅	5613ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10620ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5617ms
Deduplication.No Duplicate Events In Batch	✅	615ms
Deduplication.Different Events Have Different Uuids	✅	612ms
Compression.Sends Gzip When Enabled	✅	610ms
Batch Format.Uses Proper Batch Structure	✅	610ms
Batch Format.Flush With No Events Sends Nothing	✅	607ms
Batch Format.Multiple Events Batched Together	✅	614ms
Error Handling.Does Not Retry On 403	✅	2611ms
Error Handling.Does Not Retry On 413	✅	2613ms
Error Handling.Retries On 408	✅	5614ms

Feature_Flags Tests

✅ 17/17 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	610ms
Request Payload.Flags Request Uses V2 Query Param	✅	610ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	609ms
Request Payload.Flags Request Omits Authorization Header	✅	609ms
Request Payload.Token In Flags Body Matches Init	✅	610ms
Request Payload.Groups Round Trip	✅	609ms
Request Payload.Groups Default To Empty Object	✅	610ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	609ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	610ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	609ms
Request Lifecycle.No Flags Request On Init Alone	✅	4ms
Request Lifecycle.No Flags Request On Normal Capture	✅	609ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	1214ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	609ms
Retry Behavior.Retries Flags On 502	✅	913ms
Retry Behavior.Retries Flags On 504	✅	913ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	1212ms