update docs

Makefile

@@ -15,6 +15,9 @@ run: build  ## Run project
 build:  ## Compile project
 	go build -v -o ${PROJECT}
 
+update:  ## Update go dependencies
+	go get -u
+
 tidy:  ## Add missing and remove unused modules
 	go mod tidy
 

README.md

@@ -20,6 +20,14 @@ sanic is developed using [Nix][nix], but you can also just use the usual Golang
 
 Run local [MPD][mpd] instance for testing with `make mpd`.
 
+Update go depdendencies like this:
+
+```shell
+go get -u  # or `make update`
+go mod tidy  # or `make tidy`
+gomod2nix
+```
+
 ### ❄️ w/ Nix
 
 Enter development shell (also has [mpc][mpc] client installed for testing):