gha: moby-latest: use test.docker.com for test-channel

This is just for convenience; the script at test.docker.com is identical
to the one at get.docker.com, but uses the test-channel as default.

While at it, also setting the '-f' (fail-fast), '-s' (silent, unless
failing), '-S' (force TLS), and '-L' (follow redirects) options that are
recommended when piping the output and executing it.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

.github/workflows/moby-latest.yml

@@ -24,7 +24,7 @@ jobs:
 
       - name: Install Docker from the TEST channel
         if: ${{ matrix.install-docker-type == 'ROOTFUL' }}
-        run: curl https://get.docker.com | CHANNEL=test sh
+        run: curl -fsSL https://test.docker.com | sh
 
       - name: Setup rootless Docker
         if: ${{ matrix.install-docker-type == 'ROOTLESS' }}