Add gofumpt to format rule

Makefile

@@ -11,6 +11,7 @@ format:
 	docker run --rm -v $$PWD/schema.json:/mnt/schema.json node:alpine npx prettier /mnt/schema.json --parser json --tab-width 2 --single-quote --trailing-comma all --no-semi --arrow-parens always --print-width 120 --write
 	# Format embedded SQL
 	docker run --rm -v $$PWD/pkg/state/init.sql:/data/init.sql backplane/pgformatter --inplace /data/init.sql
+	gofumpt -w .
 
 generate: format
 	# Generate the types from the JSON schema