Fix deprecated action command

.github/workflows/test.yml

@@ -59,7 +59,7 @@ jobs:
           tar xf ffmpeg-release-4.3.1-64bit-static.tar.xz
           mkdir -p $HOME/bin
           cp ffmpeg-*/{ffmpeg,ffprobe} $HOME/bin
-          echo "::add-path::$HOME/bin"
+          echo "$HOME/bin" >> $GITHUB_PATH
 
       - name: Cache Node.js modules
         uses: actions/cache@v2
@@ -88,7 +88,7 @@ jobs:
       - name: Set env test variable (schedule)
         if: github.event_name != 'schedule'
         run: |
-          echo "::set-env name=DISABLE_HTTP_IMPORT_TESTS::true"
+          echo "DISABLE_HTTP_IMPORT_TESTS=true" >> $GITHUB_ENV
 
       - name: Run Test
         # external-plugins tests only run on schedule