Update esbuild to v0.16.5 and use new --packages=external option

Herebyfile.mjs

@@ -160,7 +160,6 @@ async function runDtsBundler(entrypoint, output) {
  * @param {BundlerTaskOptions} [taskOptions]
  *
  * @typedef BundlerTaskOptions
- * @property {string[]} [external]
  * @property {boolean} [exportIsTsObject]
  * @property {boolean} [treeShaking]
  * @property {esbuild.WatchMode} [watchMode]
@@ -179,32 +178,10 @@ function createBundler(entrypoint, outfile, taskOptions = {}) {
             sourcemap: "linked",
             sourcesContent: false,
             treeShaking: taskOptions.treeShaking,
-            external: [
-                ...(taskOptions.external ?? []),
-                "source-map-support",
-            ],
+            packages: "external",
             logLevel: "warning",
             // legalComments: "none", // If we add copyright headers to the source files, uncomment.
             plugins: [
-                {
-                    name: "no-node-modules",
-                    setup: (build) => {
-                        build.onLoad({ filter: /[\\/]node_modules[\\/]/ }, () => {
-                            // Ideally, we'd use "--external:./node_modules/*" here, but that doesn't work; we
-                            // will instead end up with paths to node_modules rather than the package names.
-                            // Instead, we'll return a load error when we see that we're trying to bundle from
-                            // node_modules, then explicitly declare which external dependencies we rely on, which
-                            // ensures that the correct module specifier is kept in the output (the non-wildcard
-                            // form works properly). It also helps us keep tabs on what external dependencies we
-                            // may be importing, which is handy.
-                            //
-                            // See: https://github.com/evanw/esbuild/issues/1958
-                            return {
-                                errors: [{ text: 'Attempted to bundle from node_modules; ensure "external" is set correctly.' }]
-                            };
-                        });
-                    }
-                },
                 {
                     name: "fix-require",
                     setup: (build) => {
@@ -448,14 +425,6 @@ const { main: tests, watch: watchTests } = entrypointBuildTask({
     bundlerOptions: {
         // Ensure we never drop any dead code, which might be helpful while debugging.
         treeShaking: false,
-        // These are directly imported via import statements and should not be bundled.
-        external: [
-            "chai",
-            "del",
-            "diff",
-            "mocha",
-            "ms",
-        ],
         watchMode: {
             onRebuild() {
                 watchTestsEmitter.emit("rebuild");