Fix typo in Makefile Slack notification command

Corrected a typo in the `Makefile` under the `scripts/govtool` directory
that caused the Slack notification command to fail. The typo in the git
revision parsing command (`git-rev-parse HEAD`) was corrected to `git
rev-parse HEAD`, ensuring that the command correctly retrieves the
current commit hash. This fix ensures that notifications sent to Slack
upon deployment include the accurate commit hash from which the
deployment was made, improving traceability and communication in
deployment processes.

scripts/govtool/Makefile

@@ -155,7 +155,7 @@ info:
 notify:
 	@:$(call check_defined, cardano_network)
 	@:$(call check_defined, env)
-	curl -X POST -H "Authorization: Bearer $$GRAFANA_SLACK_OAUTH_TOKEN" -d "channel=$$GRAFANA_SLACK_RECIPIENT" -d "text=The deploy to $(env) has been made from branch $(branch) ($(shell git-rev-parse HEAD))" https://slack.com/api/chat.postMessage
+	curl -X POST -H "Authorization: Bearer $$GRAFANA_SLACK_OAUTH_TOKEN" -d "channel=$$GRAFANA_SLACK_RECIPIENT" -d "text=The deploy to $(env) has been made from branch $(branch) ($(shell git rev-parse HEAD))" https://slack.com/api/chat.postMessage
 
 .PHONY: ssh
 ssh: