Add `vbump` and `release` targets, defaulting to Z

src/mkit.mk

@@ -26,6 +26,9 @@ rpmstuff: dist
 install: all
 	@$(MKIT_DIR)/make install
 
+release:
+	@$(MKIT_DIR)/make release_z
+
 release_x:
 	@$(MKIT_DIR)/make release_x
 
@@ -38,6 +41,9 @@ release_z:
 uninstall:
 	@$(MKIT_DIR)/make uninstall
 
+vbump:
+	@$(MKIT_DIR)/make vbump_z
+
 vbump_x:
 	@$(MKIT_DIR)/make vbump_x