chore(deps): update mysql docker tag to v9

Author: renovate-bot

.github/workflows/test-all-versions.yml

@@ -67,7 +67,7 @@ jobs:
           --health-start-period 10s
           --health-retries 20
       mysql:
-        image: mysql:5.7
+        image: mysql:9.3
         env:
           MYSQL_USER: otel
           MYSQL_PASSWORD: secret

.github/workflows/unit-test.yml

@@ -70,7 +70,7 @@ jobs:
           --health-start-period 10s
           --health-retries 20
       mysql:
-        image: mysql:5.7
+        image: mysql:9.3
         env:
           MYSQL_USER: otel
           MYSQL_PASSWORD: secret