Deprecation warning

[madadam]

(this issue was originally reported in equalitie/ouisync-plugin#9)

One normally don't see these, but appeared when I deleted the build folder in ouisync-app and rebuilt.

   Compiling num-integer v0.1.44
   Compiling time v0.1.44
   Compiling btdht v0.9.0 (https://github.com/equalitie/btdht.git#0a4176ac)
   Compiling chrono v0.4.19
   Compiling ouisync v0.1.0 (/home/inetic/work/ouisync-app/ouisync-plugin/ouisync/lib)
    Finished release [optimized] target(s) in 42.30s
    Finished release [optimized] target(s) in 0.08s
   Compiling num-integer v0.1.44
   Compiling time v0.1.44
   Compiling btdht v0.9.0 (https://github.com/equalitie/btdht.git#0a4176ac)
   Compiling chrono v0.4.19
   Compiling ouisync v0.1.0 (/home/inetic/work/ouisync-app/ouisync-plugin/ouisync/lib)
    Finished release [optimized] target(s) in 40.65s
/home/inetic/work/ouisync-app/ouisync-plugin/android/src/main/kotlin/ie/equalit/ouisync_plugin/LegacyCompatCursorWrapper.java:60: warning: [deprecation] DATA in MediaColumns has been deprecated
        if (cursor.getColumnIndex(DATA)>=0) {
                                  ^
/home/inetic/work/ouisync-app/ouisync-plugin/android/src/main/kotlin/ie/equalit/ouisync_plugin/LegacyCompatCursorWrapper.java:103: warning: [deprecation] DATA in MediaColumns has been deprecated
        if (!cursorHasDataColumn() && DATA.equalsIgnoreCase(
                                      ^
/home/inetic/work/ouisync-app/ouisync-plugin/android/src/main/kotlin/ie/equalit/ouisync_plugin/LegacyCompatCursorWrapper.java:122: warning: [deprecation] DATA in MediaColumns has been deprecated
            return(DATA);
                   ^
/home/peter/work/ouisync-app/ouisync-plugin/android/src/main/kotlin/ie/equalit/ouisync_plugin/LegacyCompatCursorWrapper.java:145: warning: [deprecation] DATA in MediaColumns has been deprecated
            result[fakeDataColumn]=DATA;
                                   ^
4 warnings
/home/inetic/.pub-cache/hosted/pub.dartlang.org/move_to_background-1.0.2/android/src/main/java/com/sayegh/move_to_background/MoveToBackgroundPlugin.java:13: warning: [deprecation] Registrar in PluginRegistry has been deprecated
import io.flutter.plugin.common.PluginRegistry.Registrar;
                                              ^
/home/inetic/.pub-cache/hosted/pub.dartlang.org/move_to_background-1.0.2/android/src/main/java/com/sayegh/move_to_background/MoveToBackgroundPlugin.java:24: warning: [deprecation] Registrar in PluginRegistry has been deprecated
  public static void registerWith(Registrar registrar) {
                                  ^
2 warnings
/home/inetic/.pub-cache/hosted/pub.dartlang.org/network_info_plus-2.1.3/android/src/main/java/dev/fluttercommunity/plus/network_info/NetworkInfo.java:46: warning: [deprecation] getConnectionInfo() in WifiManager has been deprecated
    if (wifiManager != null) wifiInfo = wifiManager.getConnectionInfo();
                                                   ^
/home/inetic/.pub-cache/hosted/pub.dartlang.org/network_info_plus-2.1.3/android/src/main/java/dev/fluttercommunity/plus/network_info/NetworkInfo.java:49: warning: [deprecation] getIpAddress() in WifiInfo has been deprecated
    if (wifiInfo != null) i_ip = wifiInfo.getIpAddress();
                                         ^
/home/inetic/.pub-cache/hosted/pub.dartlang.org/network_info_plus-2.1.3/android/src/main/java/dev/fluttercommunity/plus/network_info/NetworkInfo.java:108: warning: [deprecation] getDhcpInfo() in WifiManager has been deprecated
    DhcpInfo dhcpInfo = this.wifiManager.getDhcpInfo();
                                        ^
/home/inetic/.pub-cache/hosted/pub.dartlang.org/network_info_plus-2.1.3/android/src/main/java/dev/fluttercommunity/plus/network_info/NetworkInfo.java:122: warning: [deprecation] getConnectionInfo() in WifiManager has been deprecated
    return wifiManager == null ? null : wifiManager.getConnectionInfo();
                                                   ^
4 warnings
/home/inetic/.pub-cache/hosted/pub.dartlang.org/path_provider_android-2.0.12/android/src/main/java/io/flutter/plugins/pathprovider/PathProviderPlugin.java:165: warning: [unchecked] unchecked call to getConstructor(Class<?>...) as a member of the raw type Class
          methodChannelClass.getConstructor(
                                           ^
  where T is a type-variable:
    T extends Object declared in class Class
/home/inetic/.pub-cache/hosted/pub.dartlang.org/path_provider_android-2.0.12/android/src/main/java/io/flutter/plugins/pathprovider/PathProviderPlugin.java:165: warning: [unchecked] unchecked conversion
          methodChannelClass.getConstructor(
                                           ^
  required: Constructor<MethodChannel>
  found:    Constructor
2 warnings