fix(docker): 补充 PPA 代理替换时机

pack/Dockerfile

@@ -66,6 +66,7 @@ RUN <<EOF
         ca-certificates gnupg2 lsb-release gnupg-agent \
       && apt-get update -y \
       && add-apt-repository -y ppa:ubuntu-toolchain-r/test \
+      && sed -i 's|ppa.launchpadcontent.net|launchpad.proxy.ustclug.org|g' /etc/apt/sources.list.d/*.list \
       && apt-get update -y
 
     # Install
@@ -178,11 +179,10 @@ RUN <<EOF
         exit 0
     fi
 
-    # Add deadsnakes PPA for Python versions (use Tsinghua mirror)
+    # Add deadsnakes PPA for Python versions
     for i in 1 2 3; do
-        add-apt-repository -y ppa:deadsnakes/ppa --yes && break || { echo "Attempt $i failed, retrying in 5s..."; sleep 5; }
+        add-apt-repository -y ppa:deadsnakes/ppa && break || { echo "Attempt $i failed, retrying in 5s..."; sleep 5; }
     done
-    # Replace PPA with Tsinghua mirror
     sed -i 's|ppa.launchpadcontent.net|launchpad.proxy.ustclug.org|g' /etc/apt/sources.list.d/*.list
     apt-get update -y