Add Doppler to secret scanning partners (#16682)

Co-authored-by: Lucas Costi <lucascosti@users.noreply.github.com>

content/github/administering-a-repository/about-secret-scanning.md

@@ -36,6 +36,7 @@ When {% data variables.product.prodname_secret_scanning %} detects a set of cred
 - Databricks
 - Datadog
 - Discord
+- Doppler
 - Dropbox
 - Dynatrace
 - Finicity
@@ -90,6 +91,7 @@ Repository administrators and organization owners can grant users and team acces
 - CloudBees CodeShip
 - Databricks
 - Discord
+- Doppler
 - Dropbox
 - Dynatrace
 - Finicity