Trying a first version.

node_modules/@actions/core/lib/command.d.ts

@@ -0,0 +1,15 @@
+export interface CommandProperties {
+    [key: string]: any;
+}
+/**
+ * Commands
+ *
+ * Command Format:
+ *   ::name key=value,key=value::message
+ *
+ * Examples:
+ *   ::warning::This is the message
+ *   ::set-env name=MY_VAR::some value
+ */
+export declare function issueCommand(command: string, properties: CommandProperties, message: any): void;
+export declare function issue(name: string, message?: string): void;