chore: enable trusted publishing for releases to npm and pypi (#842)

This allows us to remove NPM and PyPI tokens from our secrets. Draft
until I also make the necessary changes in our NPM and PyPI accounts.

---
By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license

Author: iliapolo

.github/workflows/release.yml

@@ -341,6 +341,8 @@ function genericCdkProps(props: GenericProps = {}) {
     authorUrl: 'https://aws.amazon.com',
     authorOrganization: true,
     releasableCommits: pj.ReleasableCommits.featuresAndFixes('.'),
+    releaseEnvironment: 'releasing',
+    npmTrustedPublishing: true,
     jestOptions: {
       configFilePath: 'jest.config.json',
       junitReporting: false,
@@ -415,6 +417,7 @@ new JsiiBuild(cloudAssemblySchema, {
   publishToPypi: {
     distName: 'aws-cdk.cloud-assembly-schema',
     module: 'aws_cdk.cloud_assembly_schema',
+    trustedPublishing: true,
   },
   pypiClassifiers: [
     'Framework :: AWS CDK',
@@ -1411,6 +1414,7 @@ new JsiiBuild(cliLibAlpha, {
   publishToPypi: {
     distName: 'aws-cdk.cli-lib-alpha',
     module: 'aws_cdk.cli_lib_alpha',
+    trustedPublishing: true,
   },
   pypiClassifiers: [
     'Framework :: AWS CDK',