Update docs/cvdr.md to guide download cvdr from unstable, not nightly.

Author: 0405ysj

docs/cvdr.md

@@ -22,7 +22,7 @@ sudo curl -fsSL https://us-apt.pkg.dev/doc/repo-signing-key.gpg -o /etc/apt/keyr
 sudo chmod a+r /etc/apt/keyrings/android-cuttlefish-artifacts.asc
 echo \
   "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/android-cuttlefish-artifacts.asc] \
-  https://us-apt.pkg.dev/projects/android-cuttlefish-artifacts android-cuttlefish-nightly main" | \
+  https://us-apt.pkg.dev/projects/android-cuttlefish-artifacts android-cuttlefish-unstable main" | \
   sudo tee /etc/apt/sources.list.d/android-cuttlefish-artifacts.list > /dev/null
 sudo apt update
 sudo apt install cuttlefish-cvdremote