Add Deprecation message when loading from latest (#1848)

* add tests to verify if we show an error banner when users load from latest

* add deprecation manager to take care of showing a notification in case script src is being loaded from latest

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* make sure deprecation warning also register onWorker

* restore tests for banner in worker

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* add a wait selector when testing banner since worker seems to take too long to render in CI

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fix test_deprecate_loading_scripts_from_latest: I think that the
previous failure was because we actually TRIED to execute the js from
latest/core.js and it conflicted with our local copy.

But to trigger the warning is enough to have a script pointing to
pyscript.net/latest, there is no need to execute it: modify it with
type="ignore-me" and an URL which doesn't exist.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Antonio Cuni <anto.cuni@gmail.com>

pyscript.core/src/plugins/deprecations-manager.js

@@ -0,0 +1,27 @@
+// PyScript Derepcations Plugin
+import { hooks } from "../core.js";
+import { notify } from "./error.js";
+
+// react lazily on PyScript bootstrap
+hooks.main.onReady.add(checkDeprecations);
+hooks.main.onWorker.add(checkDeprecations);
+
+/**
+ * Check that there are no scripts loading from pyscript.net/latest
+ */
+function checkDeprecations() {
+    const scripts = document.querySelectorAll("script");
+    for (const script of scripts) checkLoadingScriptsFromLatest(script.src);
+}
+
+/**
+ * Check if src being loaded from pyscript.net/latest and display a notification if true
+ * * @param {string} src
+ */
+function checkLoadingScriptsFromLatest(src) {
+    if (/\/pyscript\.net\/latest/.test(src)) {
+        notify(
+            "Loading scripts from latest is deprecated and will be removed soon. Please use a specific version instead.",
+        );
+    }
+}