feat(cmd/gf): project templates update for command gf init (#3704)

cmd/gf/Makefile

@@ -1,3 +1,4 @@
+.DEFAULT_GOAL := pack
 
 pack: pack.template-single pack.template-mono pack.template-mono-app
 
@@ -17,6 +18,9 @@ pack.template-mono:
 	@cd temp && gf pack template-mono ../internal/packed/template-mono.go -n=packed -y
 	@rm -fr temp
 
+# Note:
+# command `sed` only works on MacOS.
+# use `grep -irl 'template-single' temp| xargs sed -i'' -e 's/template-single/template-mono-app/g'` on other platforms.
 pack.template-mono-app:
 	@rm -fr temp
 	@mkdir temp || exit 0
@@ -27,6 +31,6 @@ pack.template-mono-app:
 	@rm -fr temp/template-mono-app/.gitignore
 	@rm -fr temp/template-mono-app/go.mod
 	@rm -fr temp/template-mono-app/go.sum
-	@sed -i 's/template-single/template-mono-app/g' temp/template-mono-app/main.go
+	@grep -irl 'template-single' temp| xargs sed -i '' -e 's/template-single/template-mono-app/g'
 	@cd temp && gf pack template-mono-app ../internal/packed/template-mono-app.go -n=packed -y
 	@rm -fr temp