update to v5.8 with ember-cli-update

# Conflicts:
#	.github/workflows/ci.yml
#	README.md
#	tests/dummy/config/ember-try.js

Author: mansona

.eslintignore

@@ -2,6 +2,7 @@
 /blueprints/*/files/
 
 # compiled output
+/declarations/
 /dist/
 
 # misc

.github/workflows/ci.yml

@@ -87,6 +87,7 @@ jobs:
           - ember-lts-4.4
           - ember-lts-4.8
           - ember-lts-4.12
+          - ember-lts-5.4
           - ember-release
           - ember-beta
           - ember-canary

.npmignore

@@ -23,6 +23,8 @@
 /ember-cli-build.js
 /testem.js
 /tests/
+/tsconfig.declarations.json
+/tsconfig.json
 /yarn-error.log
 /yarn.lock
 .gitkeep

CONTRIBUTING.md

@@ -13,13 +13,13 @@
 
 ## Running tests
 
-* `ember test` – Runs the test suite on the current Ember version
-* `ember test --server` – Runs the test suite in "watch mode"
-* `ember try:each` – Runs the test suite against multiple Ember versions
+* `npm run test` – Runs the test suite on the current Ember version
+* `npm run test:ember -- --server` – Runs the test suite in "watch mode"
+* `npm run test:ember-compatibility` – Runs the test suite against multiple Ember versions
 
 ## Running the dummy application
 
-* `ember serve`
+* `npm run start`
 * Visit the dummy application at [http://localhost:4200](http://localhost:4200).
 
 For more information on using ember-cli, visit [https://cli.emberjs.com/release/](https://cli.emberjs.com/release/).