fix: use the correct return value for cgroup_skb

`cgroup_skb` returns 0 will block traffic in the current direction.
An example program should not block traffic, this can cause difficulties for beginners.

{{project-name}}-ebpf/src/main.rs

@@ -183,7 +183,7 @@ pub fn {{crate_name}}(ctx: SkBuffContext) -> i32 {
 
 fn try_{{crate_name}}(ctx: SkBuffContext) -> Result<i32, i32> {
     info!(&ctx, "received a packet");
-    Ok(0)
+    Ok(1)
 }
 {%- when "tracepoint" %}
 use aya_ebpf::{macros::tracepoint, programs::TracePointContext};