VOL-2980 Warnings with robotframework 3.2

Change-Id: Ic88e66525eae58b18f16f6d11136f9f7b6b0c5a5
(cherry picked from commit 008065361c71dd127d0c08274a81e598095a8437)
diff --git a/requirements.txt b/requirements.txt
index 0cf6122..5d054b9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@
 pexpect
 pylint
 pyyaml
-robotframework
+robotframework==3.1.2
 robotframework-kafkalibrary
 robotframework-lint
 robotframework-requests