fuzz: Ensure latest base images are used

Latest base image should contain Go 1.18, removing
the need of updating that ourselves, apart from
benefiting from latest changes upstream.

Signed-off-by: Paulo Gomes <paulo.gomes@weave.works>

Author: Paulo Gomes

Makefile

@@ -151,7 +151,7 @@ fuzz-build:
 	rm -rf $(BUILD_DIR)/fuzz/
 	mkdir -p $(BUILD_DIR)/fuzz/out/
 
-	docker build . --tag local-fuzzing:latest -f tests/fuzz/Dockerfile.builder
+	docker build . --pull --tag local-fuzzing:latest -f tests/fuzz/Dockerfile.builder
 	docker run --rm \
 		-e FUZZING_LANGUAGE=go -e SANITIZER=address \
 		-e CIFUZZ_DEBUG='True' -e OSS_FUZZ_PROJECT_NAME=fluxcd \

tests/fuzz/Dockerfile.builder

@@ -1,10 +1,5 @@
-FROM golang:1.18 AS go
-
 FROM gcr.io/oss-fuzz-base/base-builder-go
 
-# ensures golang 1.18 to enable go native fuzzing.
-COPY --from=go /usr/local/go /usr/local/
-
 COPY ./ $GOPATH/src/github.com/fluxcd/helm-controller/
 COPY ./tests/fuzz/oss_fuzz_build.sh $SRC/build.sh