Release v2.22.2 (#360)

Patch release for #359. No app changes.

- The Dutch store listing moved from `fastlane/metadata/android/nl` to `nl-NL`. Play rejects plain `nl`, so the Play upload of 2.22.0 and 2.22.1 failed with `nl - Invalid request`. F-Droid accepts either code.
- `check_store_listing.py` now checks every store code in `store-locales.txt` against the languages Play accepts, so CI catches this before a release.
- The 22202 "What's New" covers the 2.22 highlights, since Play users go straight from 2.21.0 to 2.22.2, and says the app is the same as 2.22.1.

Closes #359

app/build.gradle.kts

@@ -28,8 +28,8 @@ android {
         // which builds this version and then creates the matching vX.Y.Z tag +
         // release itself (versionCode is pinned to MAJOR*10000 + MINOR*100 +
         // PATCH from versionName, e.g. 2.7.2 -> 20702). See docs/RELEASING.md.
-        versionCode = 22201
-        versionName = "2.22.1"
+        versionCode = 22202
+        versionName = "2.22.2"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }