build: add go.cachedir target to makefile

Signed-off-by: Jared Watts <[email protected]>

Makefile

@@ -27,6 +27,15 @@ fallthrough: submodules
 	@echo Initial setup complete. Running make again . . .
 	@make
 
+# NOTE(hasheddan): the build submodule currently overrides XDG_CACHE_HOME in
+# order to force the Helm 3 to use the .work/helm directory. This causes Go on
+# Linux machines to use that directory as the build cache as well. We should
+# adjust this behavior in the build submodule because it is also causing Linux
+# users to duplicate their build cache, but for now we just make it easier to
+# identify its location in CI so that we cache between builds.
+go.cachedir:
+	@go env GOCACHE
+
 # Update the submodules, such as the common build scripts.
 submodules:
 	@git submodule sync