Update adopters.yaml

Adding Sicredi's blog post as reference

data/ecosystem/adopters.yaml

@@ -86,7 +86,7 @@
 - name: Sicredi
   url: https://www.sicredi.com.br/
   components: [Collector, Go, Java, Python]
-  reference: ''
+  reference: https://medium.com/sicreditech/sicredis-path-for-opentelemetry-adoption-3564fc8a743a
   contact: https://github.com/igorestevanjasinski
 - name: Skyscanner
   url: https://www.skyscanner.net/