Migrate to Bevy 0.18 (#13)

* update: enable message loop work for Windows and Linux

* update: upgrade Bevy to version 0.18 and adjust asset loader for path handling

* update: rename bevy_picking to picking in Cargo.toml

* update: remove pull_request trigger from CI and change AmbientLight to GlobalAmbientLight

* update: remove demo example from workspace and exclude it from tests

* update: remove demo package from Cargo.lock

---------

Co-authored-by: not-elm <elmgameinfo@gmail.com>

.github/workflows/ci.yml

@@ -1,7 +1,6 @@
 name: CI
 
 on:
-  pull_request:
   push:
 
 jobs:
@@ -29,7 +28,7 @@ jobs:
         if: runner.os == 'linux'
       - name: Build & run tests
         run: |
-          cargo test --workspace --no-default-features
+          cargo test --workspace --no-default-features --tests --exclude demo
   all-doc-tests:
     runs-on: ubuntu-latest
     steps: