Add support for custom suffix for container image tags. (#133)

Author: cwize1

Makefile

@@ -51,6 +51,11 @@ KUBECTL=$(TOOLS_BIN_DIR)/kubectl
 KUBE_APISERVER=$(TOOLS_BIN_DIR)/kube-apiserver
 ETCD=$(TOOLS_BIN_DIR)/etcd
 
+TAGSUFFIX_APPEND :=
+ifdef TAGSUFFIX
+    TAGSUFFIX_APPEND := -${TAGSUFFIX}
+endif
+
 # Version
 MAJOR_VER ?= 0
 MINOR_VER ?= 3
@@ -62,7 +67,7 @@ STAGING_REGISTRY := mocimages.azurecr.io
 PROD_REGISTRY := mocimages.azurecr.io
 IMAGE_NAME ?= caphcontroller
 CONTROLLER_IMG ?= $(REGISTRY)/$(IMAGE_NAME)
-TAG := $(MAJOR_VER).$(MINOR_VER).$(PATCH_VER)
+TAG := $(MAJOR_VER).$(MINOR_VER).$(PATCH_VER)${TAGSUFFIX_APPEND}
 ARCH := amd64
 ALL_ARCH = amd64 arm arm64 ppc64le s390x