fix: update placeholder value for datadog-agent in gitlab pipeline (#512)

updates placeholder value for gitlab pipeline

Author: rogeriocamorim

.gitlab-ci.yml

@@ -10,7 +10,7 @@ variables:
     value: main
   AGENT_VERSION:
     description: "Latest release version of the datadog-agent to tag the build with."
-    value: "7.55.1"
+    value: "7.61.0"
   LAYER_SUFFIX:
     description: "Suffix to be appended to the layer name (default empty)."
     value: ""