add monochrome app icon layer to support app icon theming

app/src/main/res/mipmap-anydpi-v33/ic_launcher.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+ This file is part of TinyWeatherForecastGermany.
+
+ Copyright (c) 2020,2021 Pawel Dube
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+-->
+
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@mipmap/ic_launcher_background" />
+    <foreground android:drawable="@mipmap/ic_launcher_foreground" />
+    <monochrome android:drawable="@mipmap/ic_launcher_monochrome" />
+</adaptive-icon>