upgrade @angular-devkit & ngx-build-plus to solve compilation issue

[juristr]

Cloned the repo and got a compilation error similar to this:

ERROR in : TypeError: Cannot read property 'kind' of undefined
    at declareSymbolAndAddToSymbolTable (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:27819:31)
    at bindPropertyOrMethodOrAccessor (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:28963:19)
    at bindWorker (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:28408:28)
    at bind (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:28246:13)
    at bindSourceFile (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:26593:17)
    at Object.bindSourceFile (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:26534:9)
    at initializeTypeChecker (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:56480:20)
    at Object.createTypeChecker (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:30758:9)
    at getDiagnosticsProducingTypeChecker (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85043:93)
    at /Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85171:35
    at runWithCancellationToken (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85144:24)m
    at getSemanticDiagnosticsForFileNoCache (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85167:20)
    at getAndCacheDiagnostics (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85415:26)
    at getSemanticDiagnosticsForFile (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85164:20)
    at getDiagnosticsHelper (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85106:24)
    at Object.getSemanticDiagnostics (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/typescript/lib/typescript.js:85119:20)

ERROR in ./src/main.ts
Module build failed: Error: Angular Compiler was detected but it was an instance of the wrong class.
This likely means you have several @ngtools/webpack packages installed. You can check this with `npm ls @ngtools/webpack`, and then remove the extra copies.
    at Object.ngcLoader (/Users/juri/coding/workshop/codemotion/angular-elements-dashboard/node_modules/@ngtools/webpack/src/loader.js:33:15)

Upgrading the @Angular-devkit & ngx-build-plus seems to solve it 😃.

Btw, thx for sharing such great example projects 👍. Awesome job 👏

[juristr]

Just pushed another commit (for convenience reasons into this same branch) that also fixes the broken external-dashboard-tile mentioned in #4