enh: check if .env exists before exporting

Author: marco-souza

.envrc

@@ -1,5 +1,10 @@
 #! /bin/bash
 
+if [ ! -f .env ]; then
+  echo "No .env file found"
+  return
+fi
+
 # for each valid key under .env, export it
 dotenv=.env
 export $(cat $dotenv | grep -v '^#' | xargs)