Run octavia-tempest-plugin patches against stable

This patch adds gate jobs that run octavia-tempest-plugin patches
against the stable/queens and stable/rocky branches.

This will ensure that the tests take API versioning into account.

Story: 2002167
Task: 20021

Change-Id: I83813cdf444478e34fd074114f5902ba3aaddee5
diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index 2064db5..90956d8 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -8,8 +8,12 @@
     check:
       jobs:
         - octavia-v2-dsvm-noop-api
+        - octavia-v2-dsvm-noop-api-stable-rocky
+        - octavia-v2-dsvm-noop-api-stable-queens
         - octavia-v2-dsvm-noop-py35-api
         - octavia-v2-dsvm-scenario
+        - octavia-v2-dsvm-scenario-stable-rocky
+        - octavia-v2-dsvm-scenario-stable-queens
         - octavia-v2-dsvm-py35-scenario
         - octavia-v2-dsvm-scenario-centos-7
         - octavia-v2-dsvm-scenario-ubuntu-bionic:
@@ -18,7 +22,11 @@
       queue: octavia
       jobs:
         - octavia-v2-dsvm-noop-api
+        - octavia-v2-dsvm-noop-api-stable-rocky
+        - octavia-v2-dsvm-noop-api-stable-queens
         - octavia-v2-dsvm-noop-py35-api
         - octavia-v2-dsvm-scenario
+        - octavia-v2-dsvm-scenario-stable-rocky
+        - octavia-v2-dsvm-scenario-stable-queens
         - octavia-v2-dsvm-py35-scenario
         - octavia-v2-dsvm-scenario-centos-7