chore: release PocketIC v12.0.0 (#55)

Author: mraszyk

CHANGELOG.md

@@ -7,6 +7,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 
+## 12.0.0 - 2026-01-23
+
+### Added
+- New CLI option `--mainnet-registry-version` to specify the mainnet registry version to use for fetching the mainnet routing table
+  using the existing CLI option `--fetch-mainnet-routing-table`. Defaults to the latest registry version.
+
+### Changed
+- The CLI option `--fetch-mainnet-routing-table` to specify that the mainnet routing table should be fetched from the mainnet registry
+  does not require a file path specified as `--mainnet-routing-table`.
+- The field `blockmakers` in the argument of the endpoint `/instances/<instance_id>/update/tick`
+  has been flattened into an optional vector of blockmakers per subnet.
+
+
+
 ## 11.0.0 - 2025-12-05
 
 ### Added