notifications: add firmware version check

This adds a firmware version check that shows an error message if the
connected hub is running an older Pybricks firmware version.

Issue: https://github.com/pybricks/support/issues/482

src/utils/version.test.ts

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2021 The Pybricks Authors
+
+import { pythonVersionToSemver } from './version';
+
+describe('pythonVersionToSemver', () => {
+    test.each([
+        ['v1.0.0', 'v1.0.0'],
+        ['v1.0.0a1', 'v1.0.0-alpha.1'],
+        ['v1.0.0b2', 'v1.0.0-beta.2'],
+        ['v1.0.0c3', 'v1.0.0-candidate.3'],
+        ['v1.0.0f4', 'v1.0.0-final.4'],
+    ])('valid version %s', (version, expected) => {
+        expect(pythonVersionToSemver(version)).toBe(expected);
+    });
+
+    test('invalid version', () => {
+        expect(() => pythonVersionToSemver('not a version')).toThrow();
+    });
+});

src/utils/version.ts

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2021 The Pybricks Authors
+
+import * as semver from 'semver';
+
+/**
+ * Converts a Python short version string (e.g. '1.0.0b1') to a valid semver
+ * string (e.g. 1.0.0-beta.1).
+ *
+ * @param version The Python version string.
+ * @returns A modified version string that is a valid semver.
+ */
+export function pythonVersionToSemver(version: string): string {
+    const newVersion = version
+        .replace('a', '-alpha.')
+        .replace('b', '-beta.')
+        .replace('c', '-candidate.')
+        .replace('f', '-final.');
+
+    if (!semver.valid(newVersion)) {
+        throw new Error('invalid version');
+    }
+
+    return newVersion;
+}