Bump @types/webextension-polyfill from 0.10.7 to 0.12.1 (#259)

* Bump @types/webextension-polyfill from 0.10.7 to 0.12.1

Bumps [@types/webextension-polyfill](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/webextension-polyfill) from 0.10.7 to 0.12.1.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/webextension-polyfill)

---
updated-dependencies:
- dependency-name: "@types/webextension-polyfill"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* update nvmrc; fix typing

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Graham Langford <grahamlangford87@gmail.com>

.nvmrc

@@ -1 +1 @@
-18
+20.12.0

package.json

@@ -40,7 +40,7 @@
     "@sindresorhus/tsconfig": "^6.0.0",
     "@types/chrome": "^0.0.270",
     "@types/tape": "^5.6.4",
-    "@types/webextension-polyfill": "^0.10.7",
+    "@types/webextension-polyfill": "^0.12.1",
     "buffer": "^6.0.3",
     "eslint": "^8.57.0",
     "eslint-config-pixiebrix": "^0.39.0",

source/receiver.ts

@@ -27,7 +27,7 @@ export function isMessengerMessage(message: unknown): message is Message {
 function onMessageListener(
   message: unknown,
   sender: Sender,
-): Promise<unknown> | void {
+): Promise<unknown> | undefined {
   if (!isMessengerMessage(message)) {
     // TODO: Add test for this eventuality: ignore unrelated messages
     return;

source/test/contentscript/fixtures/unrelatedMessageListener.ts

@@ -1,14 +1,15 @@
 browser.runtime.onMessage.addListener(
-  (message: unknown): Promise<string> | void => {
+  (message: unknown): Promise<string> | undefined => {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     if ((message as any)?.type === "sleep") {
       console.log(
         "I’m an unrelated message listener, but I'm replying anyway to",
-        { message }
+        { message },
       );
       return Promise.resolve("/r/nosleep");
     }
 
     console.log("I’m an unrelated message listener. I’ve seen", { message });
-  }
+    return undefined;
+  },
 );