[CI] Update GitHub Actions:

- Adds Ruby 3.0 tests
- Removes Ruby 2.6 and 2.7 tests

Author: picandocodigo

.github/workflows/2.7.yml

@@ -1,21 +1,20 @@
-name: Ruby 2.6
+name: Ruby 3.0
 on:
   push:
     branches:
-      - main
+      - 8.x
   pull_request:
     branches:
-      - main
-  workflow_dispatch:
-    branches:
-      - '*'
+      - 8.x
 jobs:
   tests:
     env:
-      TEST_ES_SERVER: http://localhost:9200
-      RAILS_VERSIONS: '5.0,6.0'
+      ELASTICSEARCH_URL: http://localhost:9200
+      RAILS_VERSIONS: ${{ matrix.rails }}
     strategy:
       fail-fast: false
+      matrix:
+        rails: [ '6.1', '7.0' ]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -27,10 +26,11 @@ jobs:
         sudo sysctl -w vm.max_map_count=262144
     - uses: elastic/elastic-github-actions/elasticsearch@master
       with:
-        stack-version: 7.x-SNAPSHOT
+        stack-version: 8.11.0-SNAPSHOT
+        security-enabled: false
     - uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 2.6
+        ruby-version: 3.0
     - name: Bundle
       run: |
         sudo apt-get install libsqlite3-dev