bump middleman-hashicorp to 0.3.40 and exclude guide rendering (#5847)

* bump middleman-hashicorp to 0.3.40 and exclude guide rendering

* add notes to Makefile for volume mounts hack PR#5847

* make note of the PR number in the comment

website/Makefile

@@ -1,4 +1,8 @@
-VERSION?="0.3.35"
+VERSION?="0.3.40"
+
+# The volume mounting steps are a way to exclude all the consul docs from being built
+# in the Consul site build process while still including the index.html page that points
+# users to learn.hashicorp.com. See PR#5847.
 
 build:
 	@echo "==> Starting build in Docker..."
@@ -7,6 +11,8 @@ build:
 		--rm \
 		--tty \
 		--volume "$(shell pwd):/website" \
+		--volume "/website/source/docs/guides" \
+		--volume "$(shell pwd)/source/docs/guides/index.html.md:/website/source/docs/guides/index.html.md" \
 		-e "ENV=production" \
 		hashicorp/middleman-hashicorp:${VERSION} \
 		bundle exec middleman build --verbose --clean
@@ -20,6 +26,8 @@ website:
 		--publish "4567:4567" \
 		--publish "35729:35729" \
 		--volume "$(shell pwd):/website" \
+		--volume "/website/source/docs/guides" \
+		--volume "$(shell pwd)/source/docs/guides/index.html.md:/website/source/docs/guides/index.html.md" \
 		hashicorp/middleman-hashicorp:${VERSION}
 
 .PHONY: build website