🏃 add apidiff to verify.sh

Makefile

@@ -38,6 +38,7 @@ export GO111MODULE=on
 TOOLS_DIR := hack/tools
 TOOLS_BIN_DIR := $(TOOLS_DIR)/bin
 GOLANGCI_LINT := $(abspath $(TOOLS_BIN_DIR)/golangci-lint)
+GO_APIDIFF := $(abspath $(TOOLS_BIN_DIR)/go-apidiff)
 
 # The help will print out all targets with their descriptions organized bellow their categories. The categories are represented by `##@` and the target descriptions by `##`.
 # The awk commands is responsible to read the entire set of makefiles included in this invocation, looking for lines of the file as xyz: ## something, and then pretty-format the target and help. Then, if there's a line with ##@ something, that gets pretty-printed as a category.
@@ -60,7 +61,10 @@ test: ## Run the script check-everything.sh which will check all.
 ## --------------------------------------
 
 $(GOLANGCI_LINT): $(TOOLS_DIR)/go.mod # Build golangci-lint from tools folder.
-	cd $(TOOLS_DIR); go build -tags=tools -o bin/golangci-lint github.com/golangci/golangci-lint/cmd/golangci-lint
+	cd $(TOOLS_DIR) && go build -tags=tools -o bin/golangci-lint github.com/golangci/golangci-lint/cmd/golangci-lint
+
+$(GO_APIDIFF): $(TOOLS_DIR)/go.mod # Build go-apidiff from tools folder.
+	cd $(TOOLS_DIR) && go build -tags=tools -o bin/go-apidiff github.com/joelanford/go-apidiff
 
 ## --------------------------------------
 ## Linting

hack/tools/go.mod

@@ -2,4 +2,7 @@ module sigs.k8s.io/controller-runtime/hack/tools
 
 go 1.13
 
-require github.com/golangci/golangci-lint v1.23.6
+require (
+	github.com/golangci/golangci-lint v1.23.6
+	github.com/joelanford/go-apidiff v0.0.0-20191206194835-106bcff5f060
+)