fix: pip-sample/testing_requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-3266406
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-3319450
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5496950
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5750790
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5880505
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5932095
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-6041515
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-6230369
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-6370660
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERCORE-3063766
- 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-SQLPARSE-6615674
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-5537286
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-5840803
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-6041512

pip-sample/testing_requirements.txt

@@ -21,7 +21,7 @@ Jinja2==2.11.3
 jsonschema==2.6.0
 jupyter==1.0.0
 jupyter-client==5.2.3
-jupyter-core==4.4.0
+jupyter-core==4.11.2
 kiwisolver==1.0.1
 MarkupSafe==1.0
 matplotlib==2.2.2
@@ -55,7 +55,7 @@ simplegeneric==0.8.1
 six==1.11.0
 terminado==0.8.1
 testpath==0.4.1
-tornado==5.1.1
+tornado==6.3.3
 traitlets==4.3.2
 tweepy==3.6.0
 urllib3==1.26.5
@@ -65,4 +65,5 @@ webencodings==0.5.1
 Werkzeug==0.15.3
 widgetsnbextension==3.4.2
 xlrd==1.1.0
-django==3.2.16
+django==3.2.25
+sqlparse>=0.5.0 # not directly required, pinned by Snyk to avoid a vulnerability