Remove default workflow

.github/workflows/main.yml

@@ -1,27 +0,0 @@
-name: Ruby
-
-on:
-  push:
-    branches:
-      - initial-implementation
-
-  pull_request:
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    name: Ruby ${{ matrix.ruby }}
-    strategy:
-      matrix:
-        ruby:
-          - '2.6.8'
-
-    steps:
-    - uses: actions/checkout@v3
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
-      with:
-        ruby-version: ${{ matrix.ruby }}
-        bundler-cache: true
-    - name: Run the default task
-      run: bundle exec rake