Update mockgen to v1.6.0

Author: Cecile Robert-Michon

Makefile

@@ -77,7 +77,7 @@ KUSTOMIZE_VER := v4.0.4
 KUSTOMIZE_BIN := kustomize
 KUSTOMIZE := $(TOOLS_BIN_DIR)/$(KUSTOMIZE_BIN)-$(KUSTOMIZE_VER)
 
-MOCKGEN_VER := v1.5.0
+MOCKGEN_VER := v1.6.0
 MOCKGEN_BIN := mockgen
 MOCKGEN := $(TOOLS_BIN_DIR)/$(MOCKGEN_BIN)-$(MOCKGEN_VER)