chore: update CI to use ubuntu-latest and JDK 21, adjust release naming

- Changed runs-on from macos-12 to ubuntu-latest for faster builds
- Updated JDK from 11 to 21 to match project requirements
- Added 'on: push' trigger to build on push to master branch
- Modified release name and tag to include version and build number format

.github/workflows/main.yml

@@ -6,6 +6,11 @@ on:
       - master
   workflow_dispatch:
 
+env:
+  VERSION: "1.4"
+  BUILD_NUMBER: ${{ github.run_number }}
+  RELEASE_NAME: "abyss-dl-${{ env.VERSION }}-build${{ env.BUILD_NUMBER }}"
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
@@ -17,11 +22,6 @@ jobs:
     permissions:
       contents: write
 
-    env:
-      VERSION: "1.4"
-      BUILD_NUMBER: ${{ github.run_number }}
-      RELEASE_NAME: "abyss-dl-${{ env.VERSION }}-build${{ env.BUILD_NUMBER }}"
-
     steps:
       - name: Set up JDK 21
         uses: actions/setup-java@v4