Add new export_diagnostics feature flag

src/feature-flags.ts

@@ -36,6 +36,7 @@ export interface FeatureEnablement {
 export enum Feature {
   CliConfigFileEnabled = "cli_config_file_enabled",
   DisableKotlinAnalysisEnabled = "disable_kotlin_analysis_enabled",
+  ExportDiagnosticsEnabled = "export_diagnostics_enabled",
   MlPoweredQueriesEnabled = "ml_powered_queries_enabled",
   UploadFailedSarifEnabled = "upload_failed_sarif_enabled",
 }
@@ -60,6 +61,10 @@ export const featureConfig: Record<
     envVar: "CODEQL_ACTION_UPLOAD_FAILED_SARIF",
     minimumVersion: "2.11.3",
   },
+  [Feature.ExportDiagnosticsEnabled]: {
+    envVar: "CODEQL_ACTION_EXPORT_DIAGNOSTICS",
+    minimumVersion: "2.12.4",
+  },
 };
 
 /**