Revert "Try the "--offline" cargo flag"

This reverts commit 1cf7fec.

Author: fornwall

src/main.rs

@@ -1178,8 +1178,6 @@ fn cargo(
     }
     cmd.arg(build_kind.exec_command());
 
-    cmd.arg("--offline");
-
     if matches!(build_kind, BuildKind::Normal) && run_quietly {
         cmd.arg("-q");
     }