fix: improve Dockerfile syntax for package installation and cleanup

Author: Gezi-lzq

.github/workflows/table-topic-playground-test.yml

@@ -25,10 +25,17 @@ jobs:
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v3
 
+    - name: Cache Docker layers
+      uses: actions/cache@v4
+      with:
+        path: /tmp/.buildx-cache
+        key: ${{ runner.os }}-buildx-${{ github.sha }}
+        restore-keys: |
+          ${{ runner.os }}-buildx-
+
     - name: Run all scenario tests
       working-directory: table-topic-solutions/playground
       run: just test-all
-      timeout-minutes: 900
 
     - name: Cleanup
       if: always()

table-topic-solutions/playground/tools/kafka-client/Dockerfile

@@ -6,8 +6,8 @@ USER root
 RUN microdnf update -y && microdnf install -y \
     maven \
     gcc-c++ \
-    python3-devel && \
-    microdnf clean all
+    python3-devel \
+    && microdnf clean all
 
 RUN pip3 install --user grpcio-tools