2.19.0 — drag to reschedule, bulk delete from search, onboarding wizard

Bumps versionName to 2.19.0 (code 21900), which is what triggers the
release when this branch merges to main.

Closes #68
Closes #80
Closes #123
Closes #163

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 = 21801
-        versionName = "2.18.1"
+        versionCode = 21900
+        versionName = "2.19.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }