fix: remove direct projen dependency, only upgrade deps weekly (#320)

The direct `projen` dependency leads to class conflicts in downstream
TypeScript repositories, if downstream packages have their own
dependency on `projen`.

There will be multiple copies of `projen` in the dependency tree,
and every class inside those copies will count as a different,
incompatible class.

Remove the direct dependency, we only need a
`peerDependency`+`devDependency`.

.projenrc.ts

@@ -1,3 +1,4 @@
+import { UpgradeDependenciesSchedule } from 'projen/lib/javascript';
 import { generateYarnMonorepoOptions } from './projenrc/yarn-monorepo-options';
 import { CdklabsJsiiProject } from './src';
 
@@ -9,14 +10,18 @@ const project = new CdklabsJsiiProject({
   defaultReleaseBranch: 'main',
   name: 'cdklabs-projen-project-types',
   repositoryUrl: 'https://github.com/cdklabs/cdklabs-projen-project-types.git',
-  devDeps: ['@jsii/spec', 'jsii-reflect'],
-  deps: ['projen'],
+  devDeps: ['@jsii/spec', 'jsii-reflect', '[email protected]'],
   bundledDeps: ['yaml'],
   peerDeps: ['projen'],
   enablePRAutoMerge: true,
   cdklabsPublishingDefaults: false,
   upgradeCdklabsProjenProjectTypes: false, // that is this project!
   setNodeEngineVersion: false,
+  depsUpgradeOptions: {
+    workflowOptions: {
+      schedule: UpgradeDependenciesSchedule.WEEKLY,
+    },
+  },
   peerDependencyOptions: {
     pinnedDevDependency: false,
   },