docs: update seccomp documentation with Podman example link

Replace outdated TODO comment with accurate information about runc's seccomp support.
Add reference to Podman's default seccomp profile as an example.

This provides users with a practical starting point for creating
custom seccomp configurations.

Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>

Author: osamakader

libcontainer/SPEC.md

@@ -367,7 +367,12 @@ profile <profile_name> flags=(attach_disconnected,mediate_deleted) {
 }
 ```
 
-*TODO: seccomp work is being done to find a good default config*
+*Seccomp filtering is supported, users can provide their own seccomp profile*
+
+**Example seccomp profile:**
+An example seccomp profile based on Podman's default configuration is available at:https://github.com/containers/common/blob/main/pkg/seccomp/seccomp.json
+
+This profile can be used as a starting point for creating custom seccomp configurations.
 
 ### Runtime and Init Process