eve: Deactivate minor version downgrade on this branch

Since we bump etcd version in development/2.8 we cannot downgrade from
development/2.8 to a version 2.7.x, so deactivate downgrade test for
minor version in the CI

Sees: #1750

eve/main.yml

@@ -753,7 +753,9 @@ stages:
           name: Trigger upgrade and downgrade test stages simultaneously
           stage_names:
             - single-node-upgrade-centos
-            - single-node-downgrade-centos
+            # NOTE: Deactivate minor downgrade on this branch
+            # See: https://github.com/scality/metalk8s/issues/1750
+            #- single-node-downgrade-centos
           waitForFinish: True
 
   create-upload-testrail-objects:
@@ -1638,7 +1640,9 @@ stages:
           stage_names:
             - snapshot-single-node-upgrades
             - snapshot-multi-node-upgrades
-            - single-node-downgrade-promoted-centos
+            # NOTE: Deactivate minor downgrade on this branch
+            # See: https://github.com/scality/metalk8s/issues/1750
+            #- single-node-downgrade-promoted-centos
 
   snapshot-single-node-upgrades:
     # NOTE: This stage just set `environment_type` property to