Update pip requirements to be more strict

PROD-35446

Change-Id: If34899d8fdb271bf29a2b88da9b2e1e053d55357
diff --git a/test_set/cvp-sanity/requirements.txt b/test_set/cvp-sanity/requirements.txt
index 49d6280..881d76e 100644
--- a/test_set/cvp-sanity/requirements.txt
+++ b/test_set/cvp-sanity/requirements.txt
@@ -1,9 +1,10 @@
 pytest==3.7.1
 pytest-rerunfailures==7.0
-requests>=2.20.0
-flake8
-PyYAML
+requests==2.24.0
+flake8==3.8.3
+PyYAML==5.3.1
 python-jenkins==1.7.0
 pygerrit2==2.0.9
-gitpython
-ldap3
+GitPython==3.1.7
+ldap3==2.7
+