Explicitly import performance for Node 12 compatibility

src/analyze-action.ts

@@ -1,3 +1,6 @@
+// We need to import `performance` on Node 12
+import { performance } from "perf_hooks";
+
 import * as core from "@actions/core";
 
 import * as actionsUtil from "./actions-util";

src/config-utils.ts

@@ -1,5 +1,7 @@
 import * as fs from "fs";
 import * as path from "path";
+// We need to import `performance` on Node 12
+import { performance } from "perf_hooks";
 
 import * as yaml from "js-yaml";
 import * as semver from "semver";