Update Makefile

Signed-off-by: Varad Gupta <114755221+vr-varad@users.noreply.github.com>

Author: vr-varad

Makefile

@@ -51,4 +51,4 @@ check-go:
 ## Update the academy-theme package to latest version
 theme-update:
 	echo "Updating to latest academy-theme..." && \
-	hugo mod get -u
+	hugo mod get github.com/layer5io/academy-theme