fix: samples/dnn/dnn_model_runner/dnn_conversion/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-NUMPY-2321964
- https://snyk.io/vuln/SNYK-PYTHON-NUMPY-2321966
- https://snyk.io/vuln/SNYK-PYTHON-NUMPY-2321970
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-10877916
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-15674461
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-15870164
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-15873763
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-15873848
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-15873849
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-15873851
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-6231769
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-6274390
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-7231121
- https://snyk.io/vuln/SNYK-PYTHON-ONNX-9510927
- https://snyk.io/vuln/SNYK-PYTHON-PROTOBUF-10364902
- https://snyk.io/vuln/SNYK-PYTHON-PROTOBUF-15090738
- https://snyk.io/vuln/SNYK-PYTHON-SENTENCEPIECE-15091567

Author: snyk-bot

samples/dnn/dnn_model_runner/dnn_conversion/requirements.txt

@@ -1,6 +1,6 @@
 # Python 3.7.5
-onnx>=1.7.0
-numpy>=1.19.1
+onnx>=1.21.0
+numpy>=1.22.2
 
 torch>=1.5.1
 torchvision>=0.6.1
@@ -12,4 +12,6 @@ paddlepaddle>=2.0.0
 paddlepaddle-gpu>=2.0.0
 paddlehub>=2.1.0
 paddle2onnx>=0.5.1
-paddleseg>=2.0.0
+paddleseg>=2.0.0
+protobuf>=5.29.6 # not directly required, pinned by Snyk to avoid a vulnerability
+sentencepiece>=0.2.1 # not directly required, pinned by Snyk to avoid a vulnerability