Clean CHANGELOG_PENDING.md after v3.18.0 release
### Improvements
-- [ci] - Adds CI detector for Buildkite
- [#7933](https://github.com/pulumi/pulumi/pull/7933)
-
-- [cli] - Add `--exclude-protected` flag to `pulumi destroy`.
- [#8359](https://github.com/pulumi/pulumi/pull/8359)
-
-- [cli] Add the ability to use `pulumi org set [name]` to set a default org
- to use when creating a stacks in the Pulumi Service backend or self-hosted Service.
- [#8352](https://github.com/pulumi/pulumi/pull/8352)
-
-- [schema] Add IsOverlay option to disable codegen for particular types.
- [#8338](https://github.com/pulumi/pulumi/pull/8338)
- [#8425](https://github.com/pulumi/pulumi/pull/8425)
-
-- [sdk/dotnet] - Marshal output values.
- [#8316](https://github.com/pulumi/pulumi/pull/8316)
-
-- [sdk/python] - Unmarshal output values in component provider.
- [#8212](https://github.com/pulumi/pulumi/pull/8212)
-
-- [sdk/nodejs] - Unmarshal output values in component provider.
- [#8205](https://github.com/pulumi/pulumi/pull/8205)
-
-- [sdk/nodejs] - Allow returning failures from Call in the provider without setting result outputs.
- [#8424](https://github.com/pulumi/pulumi/pull/8424)
-
-- [sdk/go] - Allow specifying Call failures from the provider.
- [#8424](https://github.com/pulumi/pulumi/pull/8424)
-
-- [codegen/nodejs] - Program generator now uses `fnOutput` forms where
- appropriate, simplifying auto-generated examples.
- [#8434](https://github.com/pulumi/pulumi/pull/8434)
### Bug Fixes
-- [engine] - Compute dependents correctly during targeted deletes.
- [#8360](https://github.com/pulumi/pulumi/pull/8360)
-
-- [cli/engine] - Update command respects `--target-dependents`.
- [#8395](https://github.com/pulumi/pulumi/pull/8395)
-
-- [docs] - Fix broken lists in dotnet docs.
- [docs#6558](https://github.com/pulumi/docs/issues/6558)
