flatpak: Update manifest

.gitignore

@@ -1,3 +1,4 @@
+/.flatpak
 /.flatpak-builder
 /.vscode
 /build

de.johrpan.musicus.json

@@ -25,7 +25,7 @@
             "--share=network"
         ],
         "env" : {
-            "RUSTFLAGS" : "-L /app/lib",
+            "RUSTFLAGS" : "-L=/app/lib",
             "CARGO_HOME" : "/run/build/musicus/cargo",
             "RUST_BACKTRACE" : "1",
             "RUST_LOG" : "musicus=debug"
@@ -78,28 +78,6 @@
                 }
             ]
         },
-        {
-            "name" : "libadwaita",
-            "buildsystem" : "meson",
-            "config-opts" : [
-                "-Dintrospection=enabled",
-                "-Dtests=false",
-                "-Dexamples=false",
-                "-Dvapi=false",
-                "-Dglade_catalog=disabled"
-            ],
-            "cleanup" : [
-                "/include",
-                "/lib/pkgconfig"
-            ],
-            "sources" : [
-                {
-                    "type" : "git",
-                    "url" : "https://gitlab.gnome.org/exalm/libadwaita.git",
-                    "branch" : "main"
-                }
-            ]
-        },
         {
             "name" : "musicus",
             "builddir" : true,