Update monthly_album_digest.yaml

Author: usefulalgorithm

.github/workflows/monthly_album_digest.yaml

@@ -35,4 +35,4 @@ jobs:
             -F from="Mailgun Sandbox <postmaster@${{ secrets.MAILGUN_SERVER }}>" \
             -F to="Tsung-Ju Lii <[email protected]>" \
             -F subject="Monthly Digest" \
-            --form text=<body.txt
+            -F text=@body.txt