fix(cloudformation-diff): @aws-sdk/client-cloudformation should be a peer dependency (#478)

The function signature of `fullDiff` depends on the
`DescribeChangeSetOutput` type from `@aws-sdk/client-cloudformation`.
Therefore this package should be a peer dependency, not a dev
dependency.

Updates the dependency type, and adds the minimal version as a devDep to
ensure we stay compatible. I needed to add `0BSD` into the license
checker since one of the transitive dependencies use it. It is an
approved license.

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

Author: mrgrain

.projenrc.ts

@@ -358,7 +358,7 @@ function genericCdkProps(props: GenericProps = {}) {
     },
     typescriptVersion: TYPESCRIPT_VERSION,
     checkLicenses: props.private ? undefined : {
-      allow: ['Apache-2.0', 'MIT', 'ISC', 'BSD-3-Clause'],
+      allow: ['Apache-2.0', 'MIT', 'ISC', 'BSD-3-Clause', '0BSD'],
     },
     ...props,
   } satisfies Partial<yarn.TypeScriptWorkspaceOptions>;
@@ -444,6 +444,12 @@ const cloudFormationDiff = configureProject(
     name: '@aws-cdk/cloudformation-diff',
     description: 'Utilities to diff CDK stacks against CloudFormation templates',
     srcdir: 'lib',
+    devDeps: [
+      'fast-check',
+    ],
+    peerDeps: [
+      '@aws-sdk/client-cloudformation@^3',
+    ],
     deps: [
       '@aws-cdk/aws-service-spec',
       '@aws-cdk/service-spec-types',
@@ -453,7 +459,6 @@ const cloudFormationDiff = configureProject(
       'string-width@^4',
       'table@^6',
     ],
-    devDeps: ['@aws-sdk/client-cloudformation', 'fast-check'],
     // FIXME: this should be a jsii project
     // (EDIT: or should it? We're going to bundle it into aws-cdk-lib)
     tsconfig: {