Add new metrics to example

docs/observability.md

@@ -33,4 +33,20 @@ telefonistka_github_github_rest_api_client_rate_remaining 99668
 # HELP telefonistka_webhook_server_webhook_hits_total The total number of validated webhook hits
 # TYPE telefonistka_webhook_server_webhook_hits_total counter
 telefonistka_webhook_server_webhook_hits_total{parsing="successful"} 8
+# HELP telefonistka_github_commit_status_updates_total The total number of commit status updates, and their status (success/pending/failure)
+# TYPE telefonistka_github_commit_status_updates_total counter
+telefonistka_github_commit_status_updates_total{repo_slug="foo/bar2",status="error"} 1
+telefonistka_github_commit_status_updates_total{repo_slug="foo/bar2",status="pending"} 1
+# HELP telefonistka_github_open_promotion_prs The total number of open PRs with promotion label
+# TYPE telefonistka_github_open_promotion_prs gauge
+telefonistka_github_open_promotion_prs{repo_slug="foo/bar1"} 0
+telefonistka_github_open_promotion_prs{repo_slug="foo/bar2"} 10
+# HELP telefonistka_github_open_prs The total number of open PRs
+# TYPE telefonistka_github_open_prs gauge
+telefonistka_github_open_prs{repo_slug="foo/bar1"} 0
+telefonistka_github_open_prs{repo_slug="foo/bar2"} 21
+# HELP telefonistka_github_open_prs_with_pending_telefonistka_checks The total number of open PRs with pending Telefonistka checks(excluding PRs with very recent commits)
+# TYPE telefonistka_github_open_prs_with_pending_telefonistka_checks gauge
+telefonistka_github_open_prs_with_pending_telefonistka_checks{repo_slug="foo/bar1"} 0
+telefonistka_github_open_prs_with_pending_telefonistka_checks{repo_slug="foo/bar2"} 0
 ```