Test only last 5 releases (#7105)

Author: friedrichg

.github/workflows/test-build-deploy.yml

@@ -238,11 +238,8 @@ jobs:
           docker pull consul:1.8.4
           docker pull gcr.io/etcd-development/etcd:v3.4.7
           if [ "$TEST_TAGS" = "integration_backward_compatibility" ]; then
-            docker pull quay.io/cortexproject/cortex:v1.13.2
-            docker pull quay.io/cortexproject/cortex:v1.14.1
-            docker pull quay.io/cortexproject/cortex:v1.15.3
             docker pull quay.io/cortexproject/cortex:v1.16.1
-            docker pull quay.io/cortexproject/cortex:v1.17.1
+            docker pull quay.io/cortexproject/cortex:v1.17.2
             docker pull quay.io/cortexproject/cortex:v1.18.1
             docker pull quay.io/cortexproject/cortex:v1.19.1
             docker pull quay.io/cortexproject/cortex:v1.20.0

integration/backward_compatibility_test.go

@@ -32,13 +32,11 @@ var (
 	// Per https://cortexmetrics.io/docs/configuration/v1guarantees/#flags-config-and-minor-version-upgrades,
 	// we only need to support backward compatibility for the last 3 minor versions.
 	previousVersionImages = map[string]*versionsImagesFlags{
-		"quay.io/cortexproject/cortex:v1.16.0": nil,
 		"quay.io/cortexproject/cortex:v1.16.1": nil,
-		"quay.io/cortexproject/cortex:v1.17.0": nil,
-		"quay.io/cortexproject/cortex:v1.17.1": nil,
-		"quay.io/cortexproject/cortex:v1.18.0": nil,
+		"quay.io/cortexproject/cortex:v1.17.2": nil,
 		"quay.io/cortexproject/cortex:v1.18.1": nil,
-		"quay.io/cortexproject/cortex:v1.19.0": nil,
+		"quay.io/cortexproject/cortex:v1.19.1": nil,
+		"quay.io/cortexproject/cortex:v1.20.0": nil,
 	}
 )