docs: update

Signed-off-by: Carlos Alexandro Becker <[email protected]>

Author: caarlos0

CONTRIBUTING.md

@@ -3,5 +3,11 @@
 To build and publish all images, run:
 
 ```sh
+direnv allow .
 make release-base release-goreleaser release-goreleaserpro
 ```
+
+## Direnv
+
+Make sure direnv is set up to load from `.env` directly (it's disabled by
+default in recent versions).