Update AWC ECS container id regex (#886)

* Update AWC ECS container id regex

We have new evidence that ID part may end in 9 digits not just 10 digits.

* Update specs/agents/metadata.md

specs/agents/metadata.md

@@ -110,7 +110,7 @@ On Linux, the container ID and some of the Kubernetes metadata can be extracted
 
     - `^[[:xdigit:]]{64}$`
     - `^[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4,}$`
-    - `^[[:xdigit:]]{32}-[[:digit:]]{10}$` (AWS ECS/Fargate environments)
+    - `^[[:xdigit:]]{32}-[[:digit:]]{1,10}$` (AWS ECS/Fargate environments)
 
  If we match, then the basename is assumed to be a container ID.