fix: pin setup-envtest version

Latest setup-envtest requires go 1.25

go: downloading sigs.k8s.io/controller-runtime/tools/setup-envtest v0.0.0-20251020210837-fb2beabd029b
go: sigs.k8s.io/controller-runtime/tools/setup-envtest@latest: sigs.k8s.io/controller-runtime/tools/[email protected] requires go >= 1.25.0 (running go 1.24.7; GOTOOLCHAIN=local)

Signed-off-by: Fred Rolland <[email protected]>

Author: rollandf

Makefile

@@ -88,7 +88,7 @@ $(GOVERALLS): | $(BIN_DIR); $(info  building goveralls...)
 	$(call go-install-tool,$(GOVERALLS),github.com/mattn/goveralls@$(GOVERALLS_VERSION)
 
 ENVTEST := $(BIN_DIR)/setup-envtest
-ENVTEST_VERSION := latest
+ENVTEST_VERSION := release-0.21
 ENVTEST_K8S_VERSION := 1.30.0
 .PHONY: envtest
 envtest: $(ENVTEST) ## Download envtest if necessary