build AppImage at push & pull-requests on master

creates AppImage at push & pull-request on master branch and uploads it as artifact.

Update create_appimage.sh

.github/scripts/setup_scrcpy.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+sudo apt update
+sudo apt install ffmpeg libsdl2-2.0-0 adb libusb-1.0-0 -y
+sudo apt install gcc git pkg-config meson ninja-build libsdl2-dev \
+                 libavcodec-dev libavdevice-dev libavformat-dev libavutil-dev \
+                 libusb-1.0-0-dev -y
+
+sudo rm -rf scrcpy
+git clone https://github.com/Genymobile/scrcpy
+cd scrcpy
+
+wget https://github.com/Genymobile/scrcpy/releases/download/v1.23/scrcpy-server-v1.23 \
+-O scrcpy-server
+
+meson x --buildtype=release --strip -Db_lto=true \
+    -Dprebuilt_server=scrcpy-server
+ninja -Cx
+
+# icon name should be same as binary name for appimage creation
+cp app/data/icon.png app/data/scrcpy.png
+
+cd ../