CI: Add Ruby 3.0 to test metrix

CI: Add Ruby 3.0 to test metrix

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4abd808..2d11679 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,7 +35,7 @@ jobs:
         options: --health-cmd="mysqladmin ping" --health-interval=10s --health-timeout=5s --health-retries=3
     strategy:
       matrix:
-        ruby: ["2.7", "2.6", "2.5"]
+        ruby: ["3.0", "2.7", "2.6", "2.5"]
         experimental: [false]
         include:
           - ruby: ruby-head

GitHub sha: 922f2a9d4d09b3d12b6a317d798d89f9a91cc15b