Use mk. prefix for Makefile time stamps and make git ignore them

client/containers/qldbtools/Makefile

@@ -1,8 +1,8 @@
 DBT_TARGET := client-qldbtools-container:0.1.24
 
 # Build the qldbtools container image
-dbt: client-qldbtools-container
-client-qldbtools-container:
+dbt: mk.client-qldbtools-container
+mk.client-qldbtools-container:
 	docker build -t ${DBT_TARGET} .
 	touch $@
 
@@ -14,7 +14,8 @@ dbt-run: dbt
 dbt-check: dbt
 	docker run --rm -it ${DBT_TARGET} mc-db-initial-info
 
-dbt-push: dbt
+dbt-push: mk.dbt-push
+mk.dbt-push: dbt
 	docker tag ${DBT_TARGET} ghcr.io/hohn/${DBT_TARGET} 
 	docker push ghcr.io/hohn/${DBT_TARGET}
 	touch $@

client/containers/vscode/Makefile

@@ -1,8 +1,8 @@
 all: code-server-initialized
 
 CSI_TARGET := code-server-initialized:0.1.24
-csi: code-server-initialized
-code-server-initialized:
+csi: mk.code-server-initialized
+mk.code-server-initialized:
 	docker build -t ${CSI_TARGET} .
 	touch $@
 
@@ -11,12 +11,13 @@ csi-serve: csi
 
 clean:
 	-docker rmi -f ${CSI_TARGET}
-	-rm code-server-initialized
+	-rm mk.code-server-initialized
 
 # Targets below are used after some manual setup of the container.  See README.org
 # for details
 
-csi-push: csi
+csi-push: mk.csi-push
+mk.csi-push: csi
 	docker tag ${CSI_TARGET} ghcr.io/hohn/${CSI_TARGET}
 	docker push ghcr.io/hohn/${CSI_TARGET}
 	touch $@