feat: use exec in wrapper if postHook is empty (#101)

avoid unnecesary bash process and improves signal handling

Author: adrian-gierakowski

nix/process-compose/default.nix

@@ -45,7 +45,7 @@ in
             ${config.cli.preHook}
 
             # IMPORTANT: We **must** use environment variables for everything but non-global options, otherwise the use of sub-command specific CLI options will prevent the user from passing their own subcommands reliably.
-            ${config.cli.outputs.environment} PC_CONFIG_FILES=${configFile} process-compose ${config.cli.outputs.options} "$@"
+            ${config.cli.outputs.environment} PC_CONFIG_FILES=${configFile} ${if config.cli.postHook == "" then "exec " else ""}process-compose ${config.cli.outputs.options} "$@"
 
             ${config.cli.postHook}
           '';