update README

Author: xu-cheng

README.md

@@ -4,7 +4,7 @@
 
 GitHub Action to compile LaTeX documents.
 
-It runs in [a docker image](https://github.com/xu-cheng/latex-docker) with a full [TeXLive](https://www.tug.org/texlive/) environment installed.
+It runs in [a docker container](https://github.com/xu-cheng/latex-docker) with a full [TeXLive](https://www.tug.org/texlive/) environment installed.
 
 If you want to run arbitrary commands in a TeXLive environment, use [texlive-action](https://github.com/xu-cheng/texlive-action) instead.
 
@@ -102,7 +102,8 @@ jobs:
         uses: xu-cheng/latex-action@v2
         with:
           root_file: main.tex
-      - uses: actions/upload-artifact@v3
+      - name: Upload PDF file
+        uses: actions/upload-artifact@v3
         with:
           name: PDF
           path: main.pdf