chore: fix install command order

Move `git submodule update --init` before `bundle install` to address `The path `/home/phil/kong/docs.konghq.com/app/_src/.repos/kuma/jekyll-kuma-plugins` does not exist.` during `make install` command.

Signed-off-by: Philipp Rudloff <[email protected]>

Makefile

@@ -15,9 +15,9 @@ install-prerequisites:
 
 # Installs npm packages and gems.
 install: ruby-version-check
+	git submodule update --init
 	npm ci
 	bundle install
-	git submodule update --init
 	@if [ ! -f .env ]; then cp .env.example .env; fi
 
 # Using local dependencies, starts a doc site instance on http://localhost:4000.