Update install.sh to use 'root' user for act_runner service and modify README with new installation URL

install.sh

@@ -103,12 +103,12 @@ fi
 
 # Install systemd service for act_runner
 if command -v systemctl >/dev/null 2>&1; then
-    if ! id -u act_runner >/dev/null 2>&1; then
-        useradd --system --home-dir /var/lib/act_runner --shell /usr/sbin/nologin act_runner
+    if ! id -u root >/dev/null 2>&1; then
+        useradd --system --home-dir /var/lib/act_runner --shell /usr/sbin/nologin root
     fi
 
     mkdir -p /var/lib/act_runner /etc/act_runner
-    chown -R act_runner:act_runner /var/lib/act_runner /etc/act_runner
+    chown -R root:root /var/lib/act_runner /etc/act_runner
 
     service_path="/etc/systemd/system/act-runner.service"
     cat >"$service_path" <<'EOF'
@@ -124,7 +124,7 @@ WorkingDirectory=/var/lib/act_runner
 TimeoutSec=0
 RestartSec=10
 Restart=always
-User=act_runner
+User=root
 
 [Install]
 WantedBy=multi-user.target