Update default version of packages to latest (#95)

* Update default version of packages to latest

* Fix typo in the json of the packageJsonTemplate

* Update Apps-Engine version to latest
Co-authored-by: Bradley Hilton <graywolf336@craftyn.com>

src/templates/app/packageJsonTemplate.ts

 export const packageJsonTemplate = (): string => {
     return `{
     "devDependencies": {
-        "@rocket.chat/apps-engine": "^1.12.0",
-        "@types/node": "^10.12.14",
+        "@rocket.chat/apps-engine": "^1.19.0",
+        "@types/node": "14.14.6",
         "tslint": "^5.10.0",
-        "typescript": "^2.9.1"
+        "typescript": "^4.0.5"
     }
 }`;
 };