Fix ghs_ token regex for new stateless format (#1840)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: hagould

hooks/secrets-scanner/scan-secrets.sh

@@ -30,7 +30,7 @@ PATTERNS=(
   # GitHub tokens
   "GITHUB_PAT|critical|ghp_[0-9A-Za-z]{36}"
   "GITHUB_OAUTH|critical|gho_[0-9A-Za-z]{36}"
-  "GITHUB_APP_TOKEN|critical|ghs_[0-9A-Za-z]{36}"
+  "GITHUB_APP_TOKEN|critical|ghs_[0-9A-Za-z._-]{36,}"
   "GITHUB_REFRESH_TOKEN|critical|ghr_[0-9A-Za-z]{36}"
   "GITHUB_FINE_GRAINED_PAT|critical|github_pat_[0-9A-Za-z_]{82}"