Prepare for v3.18.1 release
CHANGELOG
=========
+## 3.18.1 (2021-11-22)
+
+### Improvements
+
+- [cli] - When running `pulumi new https://github.com/name/repo`, check
+ for branch `main` if branch `master` doesn't exist.
+ [#8463](https://github.com/pulumi/pulumi/pull/8463)
+
+- [codegen/python] - Program generator now uses `fn_output` forms where
+ appropriate, simplifying auto-generated examples.
+ [#8433](https://github.com/pulumi/pulumi/pull/8433)
+
+- [codegen/go] - Program generator now uses fnOutput forms where
+ appropriate, simplifying auto-generated examples.
+ [#8431](https://github.com/pulumi/pulumi/pull/8431)
+
+- [codegen/dotnet] - Program generator now uses `Invoke` forms where
+ appropriate, simplifying auto-generated examples.
+ [#8432](https://github.com/pulumi/pulumi/pull/8432)
+
+### Bug Fixes
+
+- [cli/nodejs] - Allow specifying the tsconfig file used in Pulumi.yaml.
+ [#8452](https://github.com/pulumi/pulumi/pull/8452)
+
+- [codegen/nodejs] - Respect default values in Pulumi object types.
+ [#8400](https://github.com/pulumi/pulumi/pull/8400)
+
+- [sdk/python] - Correctly handle version checking python virtual environments.
+ [#8465](https://github.com/pulumi/pulumi/pull/8465)
+
+- [cli] - Catch expected errors in stacks with filestate backends.
+ [#8455](https://github.com/pulumi/pulumi/pull/8455)
+
+- [sdk/dotnet] - Do not attempt to serialize unknown values.
+ [#8475](https://github.com/pulumi/pulumi/pull/8475)
+
## 3.18.0 (2021-11-17)
### Improvements
