Revert "Try full image"

This reverts commit 07893b2

Author: bahusoid

.github/workflows/NetCoreTests.yml

@@ -50,7 +50,7 @@ jobs:
     - name: Set up Oracle
       if: matrix.DB == 'Oracle'
       run: |
-        docker run -d -p 1521:1521 -e APP_USER=nhibernate -e APP_USER_PASSWORD=nhibernate -e ORACLE_PASSWORD=nhibernate gvenzl/oracle-xe:18
+        docker run -d -p 1521:1521 -e APP_USER=nhibernate -e APP_USER_PASSWORD=nhibernate -e ORACLE_PASSWORD=nhibernate gvenzl/oracle-xe:18-slim
 
     - uses: actions/checkout@v2
     - name: Setup .NET