docs(k8sprocessor): add exclude to README

pkg/processor/k8sprocessor/README.md

@@ -251,6 +251,21 @@ processors:
        - key: key2
          value: value2
          op: not-equals
+
+    exclude:
+      # Configure a list of exclusion rules. For now it's possible to specify
+      # a list of pod name regexes who's records should not be enriched with metadata.
+      #
+      # Default:
+      # pods:
+      # - name: jaeger-agent
+      # - name: jaeger-collector
+      # - name: otel-collector
+      # - name: otel-agent
+      # - name: collection-sumologic-otelcol
+      pods:
+        - name: jaeger-agent
+        - name: my-agent
 ```
 
 ## RBAC