chore: upgrade adc to 0.20.0 (#2432)

Author: AlinsRan

.github/workflows/apisix-conformance-test.yml

@@ -76,7 +76,6 @@ jobs:
           ARCH: amd64
           ENABLE_PROXY: "false"
           BASE_IMAGE_TAG: "debug"
-          ADC_VERSION: "dev"
         run: |
           echo "building images..."
           make build-image

.github/workflows/apisix-e2e-test.yml

@@ -79,7 +79,6 @@ jobs:
           ARCH: amd64
           ENABLE_PROXY: "false"
           BASE_IMAGE_TAG: "debug"
-          ADC_VERSION: "dev"
         run: |
           echo "building images..."
           make build-image

Makefile

@@ -28,7 +28,7 @@ ENVTEST_K8S_VERSION = 1.30.0
 KIND_NAME ?= apisix-ingress-cluster
 
 GATEAY_API_VERSION ?= v1.2.0
-ADC_VERSION ?= 0.19.0
+ADC_VERSION ?= 0.20.0
 
 TEST_TIMEOUT ?= 80m
 TEST_DIR ?= ./test/e2e/apisix/