Upgrade my project and my external third library from Angular 11 to 12 fails because of dependencies to "ngx-filesaver" and "ngx-toastr" in my library

Question

Important : the external third library is published on a public NPM repository. It is very annoying because it means we need to publish a new version on the repository every time we do a change, even if it is a very small one. We should look for a better solution, but it is another topic.

The configuration with Angular 11:

"my-external-third-library":
    "version": "1.0"
    "peerDependencies":
        "@angular/core": "~11.2.14",
        "ngx-filesaver": "^11.0.0",
        "ngx-toastr": "^13.1.0",

"my-project"
    "version": "1.0"
    "dependencies":
        "@angular/core": "~11.2.14",
        "my-external-third-library": "1.0",
        "ngx-filesaver": "^11.0.0",
        "ngx-toastr": "^13.1.0",

npm i command is ok
ng serve command is ok

The configuration with Angular 12:

"my-external-third-library":
    "version": "1.1"
    "peerDependencies":
        "@angular/core": "~12.2.17",
        "ngx-filesaver": "^12.0.0",
        "ngx-toastr": "^14.3.0",

"my-project"
    "version": "1.1"
    "dependencies":
        "@angular/core": "~12.2.17",
        "my-external-third-library": "1.1",
        "ngx-filesaver": "^12.0.0",
        "ngx-toastr": "^14.3.0",

npm i command is ok
ng serve command fails:

C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\entry_point_finder\targeted_entry_point_finder.js:40
                throw new Error("The target entry-point \"" + invalidTarget.entryPoint.name + "\" has missing dependencies:\n" +
                ^

Error: The target entry-point "my-external-third-library" has missing dependencies:
 - ngx-toastr/public_api
 - ngx-filesaver/index

    at TargetedEntryPointFinder.findEntryPoints (C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\entry_point_finder\targeted_entry_point_finder.js:40:23)
    at C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\execution\analyze_entry_points.js:29:41
    at SingleProcessExecutorSync.SingleProcessorExecutorBase.doExecute (C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\execution\single_process_executor.js:28:29)
    at C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\execution\single_process_executor.js:57:59
    at SyncLocker.lock (C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\locking\sync_locker.js:34:24)
    at SingleProcessExecutorSync.execute (C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\execution\single_process_executor.js:57:27)
    at Object.mainNgcc (C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\src\main.js:74:25)
    at Object.process (C:\Users\my-path\node_modules\@angular\compiler-cli\ngcc\index.js:29:23)
    at NgccProcessor.processModule (C:\Users\my-path\node_modules\@ngtools\webpack\src\ngcc_processor.js:175:16)
    at C:\Users\my-path\node_modules\@ngtools\webpack\src\ivy\host.js:146:18

Any idea of what's wrong ? I am stuck with it...

An interesting point is what we see for ngx-filesaver and ngx-toastr libraries in the node_modules folder:

For Angular 11:

"ngx-filesaver": "^11.0.0"

ngx-filesaver.d.ts:

/**
 * Generated bundle index. Do not edit.
 */
export * from './index';

"ngx-toastr": "^13.1.0"

ngx-toastr.d.ts:

/**
 * Generated bundle index. Do not edit.
 */
export * from './public_api';

For Angular 12:

"ngx-filesaver": "^12.0.0"