Merge pull request #29046 from thaJeztah/pin-swagger-version

pin go-swagger 0.7.4

Makefile

@@ -147,4 +147,4 @@ swagger-gen:
 		-w /go/src/github.com/docker/docker \
 		--entrypoint hack/generate-swagger-api.sh \
 		-e GOPATH=/go \
-		quay.io/goswagger/swagger
+		quay.io/goswagger/swagger:0.7.4