Fix test action

`yarn all` doesn't necessarily add a newline at the end.
The env reader expects the EOF string to be on its own line,
so if the yarn command does not produce this, the workflow fails.

.github/workflows/test.yml

@@ -20,6 +20,7 @@ jobs:
           EOF=$(dd if=/dev/urandom bs=15 count=1 status=none | base64)
           echo "all_result<<$EOF" >> "$GITHUB_ENV"
           yarn all >> "$GITHUB_ENV"
+          echo >> "$GITHUB_ENV"  # yarn all doesn't necessarily produce a newline
           echo "$EOF" >> "$GITHUB_ENV"
         id: all
       - uses: ./