Simplify MSSQL database setup using docker exec

Instead of installing sqlcmd tools on the runner, use docker exec to run sqlcmd from within the container itself. This is much simpler and faster.

Author: gfx

.github/workflows/example.yaml

@@ -128,6 +128,11 @@ jobs:
         with:
           fetch-depth: 0
 
+      - name: Create MSSQL database
+        run: |
+          docker exec $(docker ps -q -f "ancestor=mcr.microsoft.com/mssql/server:2022-latest") \
+            /opt/mssql-tools18/bin/sqlcmd -S localhost -U SA -P "Passw0rd" -Q "CREATE DATABASE testdb;" -C
+
       - name: Preview MSSQL schema changes
         uses: ./
         with: