Bump Go to 1.21, set and use KAFKA_BOOTSTRAP_SERVERS correctly in mak…

…efile to use internal advertised listeners when running testacc under docker

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.16
+FROM golang:1.21
 
 WORKDIR /go/src/github.com/Mongey/terraform-provider-kafka/
 

GNUmakefile

@@ -1,4 +1,5 @@
 GOFMT_FILES?=$$(find . -name '*.go' |grep -v vendor)
+KAFKA_BOOTSTRAP_SERVERS ?= localhost:9092
 default: build
 
 build:
@@ -9,7 +10,7 @@ test:
 
 testacc:
 	GODEBUG=x509ignoreCN=0 \
-	KAFKA_BOOTSTRAP_SERVERS=localhost:9092 \
+	KAFKA_BOOTSTRAP_SERVERS=$(KAFKA_BOOTSTRAP_SERVERS) \
 	KAFKA_CA_CERT=../secrets/ca.crt \
 	KAFKA_CLIENT_CERT=../secrets/client.pem \
 	KAFKA_CLIENT_KEY=../secrets/client.key \

docker-compose.testacc.yaml

@@ -4,7 +4,7 @@ services:
   testacc:
     build: .
     environment:
-      KAFKA_BOOTSTRAP_SERVER: kafka1:9090,kafka2:9090,kafka3:9090
+      KAFKA_BOOTSTRAP_SERVERS: kafka1:9090,kafka2:9090,kafka3:9090
     entrypoint:
       - make
       - testacc