fix pip install whl file command

Author: yiyuan-he

.github/workflows/release-udp-exporter.yml

@@ -93,7 +93,7 @@ jobs:
 
       - name: Setup validation app
         run: |
-          pip install ../exporters/aws-otel-otlp-udp-exporter/dist/*.whl
+          pip install ./exporters/aws-otel-otlp-udp-exporter/dist/*.whl
 
       - name: Run validation test
         working-directory: exporters/aws-otel-otlp-udp-exporter/validation_app