connect: Add support for Envoy 1.20 (#11277)

.changelog/11277.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+connect: update supported envoy versions to 1.20.0, 1.19.1, 1.18.4, 1.17.4
+```

.circleci/config.yml

@@ -853,6 +853,11 @@ jobs:
     environment:
       ENVOY_VERSION: "1.19.1"
 
+  envoy-integration-test-1_20_0:
+    <<: *ENVOY_TESTS
+    environment:
+      ENVOY_VERSION: "1.20.0"
+
   # run integration tests for the connect ca providers
   test-connect-ca-providers:
     docker:
@@ -1108,6 +1113,9 @@ workflows:
       - envoy-integration-test-1_19_1:
           requires:
             - dev-build
+      - envoy-integration-test-1_20_0:
+          requires:
+            - dev-build
 
   website:
     unless: << pipeline.parameters.trigger-load-test >>

agent/xds/envoy_versioning_test.go

@@ -121,6 +121,7 @@ func TestDetermineSupportedProxyFeaturesFromString(t *testing.T) {
 		"1.17.0", "1.17.1", "1.17.2", "1.17.3", "1.17.4",
 		"1.18.0", "1.18.1", "1.18.2", "1.18.3", "1.18.4",
 		"1.19.0", "1.19.1",
+		"1.20.0",
 	} {
 		cases[v] = testcase{expect: supportedProxyFeatures{}}
 	}

agent/xds/proxysupport/proxysupport.go

@@ -7,6 +7,7 @@ package proxysupport
 //
 // see: https://www.consul.io/docs/connect/proxies/envoy#supported-versions
 var EnvoyVersions = []string{
+	"1.20.0",
 	"1.19.1",
 	"1.18.4",
 	"1.17.4",