XCSoar: update source code URLs

The project is now on GitHub, see https://www.xcsoar.org/develop/

Also use HTTPS for Web site and issue tracker URLs and remove outdated
maintainer note.

metadata/org.xcsoar.txt

@@ -1,9 +1,9 @@
 Categories:Navigation
 License:GPL-2.0
-Web Site:http://www.xcsoar.org
-Source Code:http://git.xcsoar.org/cgit/master/xcsoar.git
-Issue Tracker:http://bugs.xcsoar.org
-Changelog:http://git.xcsoar.org/cgit/master/xcsoar.git/tree/NEWS.txt
+Web Site:https://www.xcsoar.org
+Source Code:https://github.com/XCSoar/XCSoar
+Issue Tracker:https://bugs.xcsoar.org
+Changelog:https://github.com/XCSoar/XCSoar/blob/HEAD/NEWS.txt
 
 Auto Name:XCSoar
 Summary:Tactical glide computer and maps
@@ -14,7 +14,7 @@ calculation, collision avoidance and many many more features.
 .
 
 Repo Type:git
-Repo:git://git.xcsoar.org/xcsoar/master/xcsoar.git
+Repo:https://github.com/XCSoar/XCSoar
 
 Build:6.7.3,92
     commit=v6.7.3
@@ -172,12 +172,6 @@ Build:6.8.10,111
     build=make TARGET=ANDROID7 DEBUG=n TESTING=n -j`nproc`
     ndk=r15c
 
-Maintainer Notes:
-The makefile setup is not perfect, so we need to run it a few times to get it to succeed.
-
-Requires r10e (build breaks with 12b).
-.
-
 Auto Update Mode:Version v%v
 Update Check Mode:Tags
 Current Version:6.8.10