fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-GITPYTHON-6150683
- https://snyk.io/vuln/SNYK-PYTHON-JINJA2-6150717

requirements.txt

@@ -20,7 +20,7 @@ dicttoxml==1.7.4
 
 # fails on requiring newer version of setuptools
 #Flask==0.10.1
-GitPython==2.1.15
+GitPython==3.1.41
 
 # this GCP API is surprisingly awful, not using
 #google-api-python-client==1.11.0
@@ -30,7 +30,7 @@ GitPython==2.1.15
 
 humanize==0.5.1
 impyla==0.16.0
-jinja2==2.11.3
+jinja2==3.1.3
 #kazoo==2.2.1
 ldif3==3.2.2
 #MarkupSafe==0.23