Drop py36 and py37 jobs

Drop jobs as they are not supported anymore from tempest.
Bump oslo log to 5.0 to comply with global requirements.

Change-Id: I7154e488456625cea5a4f69a4f00861e03ccfa94

.zuul.yaml

@@ -1,5 +1,12 @@
 - project:
     templates:
-      - openstack-python3-victoria-jobs
-      - check-requirements
       - openstack-cover-jobs
+    check:
+      jobs:
+        - openstack-tox-pep8
+        - openstack-tox-py38
+    gate:
+      jobs:
+        - openstack-tox-pep8
+        - openstack-tox-py38
+

lower-constraints.txt

@@ -8,7 +8,7 @@ hacking>=3.0.1 # Apache-2.0
 netaddr==0.7.18
 openstackdocstheme==1.18.1
 oslo.i18n==3.20.0
-oslo.log==4.2.1
+oslo.log==4.4.0
 oslo.serialization==2.28.1
 oslo.service==1.31.0
 oslo.utils==4.4.0

requirements.txt

@@ -9,7 +9,9 @@ eventlet>=0.24.1 # MIT
 netaddr>=0.7.18 # BSD
 tenacity>=6.0.0 # Apache-2.0
 oslo.i18n>=3.20.0 # Apache-2.0
-oslo.log>=4.2.1 # Apache-2.0
+oslo.log>=4.2.1;python_version=='3.6' # Apache-2.0
+oslo.log>=4.2.1;python_version=='3.7' # Apache-2.0
+oslo.log>=4.4.0;python_version=='3.8' # Apache-2.0
 oslo.serialization>=2.28.1 # Apache-2.0
 oslo.service>=1.31.0 # Apache-2.0
 oslo.utils>=4.4.0 # Apache-2.0