1.6.12 changelog (#20635)

## Summary & Motivation

## How I Tested These Changes

CHANGES.md

@@ -1,5 +1,36 @@
 # Changelog
 
+# 1.6.12 (core) / 0.22.12 (libraries)
+
+### New
+
+- `AssetCheckResult` now has a text `description` property. Check evaluation descriptions are shown in the Checks tab on the asset details page.
+- Introduced `TimestampMetadataValue`. Timestamp metadata values are represented internally as seconds since the Unix epoch. They can be constructed using `MetadataValue.timestamp`. In the UI, they’re rendered in the local timezone, like other timestamps in the UI.
+- `AssetSelection.checks` can now accept `AssetCheckKeys` as well as `AssetChecksDefinition`.
+- [community-contribution] Metadata attached to an output at runtime (via either `add_output_metadata` or by passing to `Output`) is now available on `HookContext` under the `op_output_metadata` property. Thanks [@JYoussouf](https://github.com/JYoussouf)!
+- [experimental] `@asset`, `AssetSpec`, and `AssetOut` now accept a `tags` property. Tags are key-value pairs meant to be used for organizing asset definitions. If `"__dagster_no_value"` is set as the value, only the key will be rendered in the UI. `AssetSelection.tag` allows selecting assets that have a particular tag.
+- [experimental] Asset tags can be used in asset CLI selections, e.g. `dagster asset materialize --select tag:department=marketing`
+- [experimental][dagster-dbt] Tags can now be configured on dbt assets, using `DagsterDbtTranslator.get_tags`. By default, we take the dbt tags configured on your dbt models, seeds, and snapshots.
+- [dagster-gcp] Added get_gcs_keys sensor helper function.
+
+### Bugfixes
+
+- Fixed a bug that prevented external assets with dependencies from displaying properly in Dagster UI.
+- Fix a performance regression in loading code locations with large multi-assets.
+- [community-contribution] [dagster-databricks] Fix a bug with the `DatabricksJobRunner` that led to an inability to use dagster-databricks with Databricks instance pools. Thanks [@smats0n](https://github.com/smats0n)!
+- [community-contribution] Fixed a bug that caused a crash when external assets had hyphens in their `AssetKey`. Thanks [@maxfirman](https://github.com/maxfirman)!
+- [community-contribution] Fix a bug with `load_assets_from_package_module` that would cause a crash when any submodule had the same directory name as a dependency. Thanks [@CSRessel](https://github.com/CSRessel)!
+- [community-contribution] Fixed a mypy type error, thanks @parthshyara!
+- [community-contribution][dagster-embedded-elt] Fixed an issue where Sling assets would not properly read group and description metadata from replication config, thanks @jvyoralek!
+- [community-contribution] Ensured annotations from the helm chart properly propagate to k8s run pods, thanks @maxfirman!
+
+### Dagster Cloud
+
+- Fixed an issue in Dagster Cloud Serverless runs where multiple runs simultaneously materializing the same asset would sometimes raise a “Key not found” exception.
+- Fixed an issue when using [agent replicas](https://docs.dagster.io/dagster-cloud/deployment/agents/running-multiple-agents#running-multiple-agents-in-the-same-environment) where one replica would sporadically remove a code server created by another replica due to a race condition, leading to a “code server not found” or “Deployment not found” exception.
+- [experimental] The metadata key for specifying column schema that will be rendered prominently on the new Overview tab of the asset details page has been changed from `"columns"` to `"dagster/column_schema"`. Materializations using the old metadata key will no longer result in the Columns section of the tab being filled out.
+- [ui] Fixed an Insights bug where loading a view filtered to a specific code location would not preserve that filter on pageload.
+
 ## 1.6.11 (core) / 0.22.11 (libraries)
 
 ### Bugfixes