Bug 1926: Update version of Six

The IM now uses six 1.16.0, so the requirements-dev.txt needs to be
updated to match

Additional dependencies updated:
  lxml
  pyang
  idna
  requests

Fixes bug 1926

Change-Id: I7d8f9ca9a0fd5e0d0e2bdb1900ef247a5b41fccc
Signed-off-by: beierlm <mark.beierl@canonical.com>
diff --git a/requirements-test.txt b/requirements-test.txt
index 7f87751..b71b0f2 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -36,7 +36,7 @@
     # via
     #   -r requirements-test.in
     #   nose2
-idna==2.10
+idna==3.3
     # via
     #   requests
     #   yarl
@@ -50,7 +50,7 @@
     # via -r requirements-test.in
 pyang==2.5.2
     # via -r requirements-test.in
-requests==2.25.1
+requests==2.27.1
     # via -r requirements-test.in
 six==1.16.0
     # via nose2