[gimp] flatpak: Remove meson build

[Jehan <jehanp src gnome org>]

commit 551cc6a0ba9f85b6d785cef09bf3780b5cca139f
Author: Ondřej Míchal <harrymichal seznam cz>
Date:   Sun May 23 13:32:37 2021 +0200

    flatpak: Remove meson build
    
    GNOME SDK contains Meson since version 3.38.
    
    See https://github.com/flathub/org.gimp.GIMP/pull/97/commits/e8ea70269174dcc9c6e778892b2f8ae887bc8759

 build/flatpak/org.gimp.GIMP-nightly.json | 14 --------------
 1 file changed, 14 deletions(-)
---
diff --git a/build/flatpak/org.gimp.GIMP-nightly.json b/build/flatpak/org.gimp.GIMP-nightly.json
index 622c790ca3..f9ecd850a0 100644
--- a/build/flatpak/org.gimp.GIMP-nightly.json
+++ b/build/flatpak/org.gimp.GIMP-nightly.json
@@ -21,20 +21,6 @@
                 "/share/aclocal", "/man", "/share/man", "/share/gtk-doc",
                 "/share/vala", "*.la", "*.a" ],
     "modules": [
-        {
-            "name": "meson",
-            "buildsystem": "simple",
-            "config-opts": [ "-Dintrospection=false" ],
-            "cleanup": ["*"],
-            "sources": [
-                {
-                    "type": "archive",
-                    "url": 
"https://github.com/mesonbuild/meson/releases/download/0.54.0/meson-0.54.0.tar.gz";,
-                    "sha256": "dde5726d778112acbd4a67bb3633ab2ee75d33d1e879a6283a7b4a44c3363c27"
-                }
-            ],
-            "build-commands": [ "python3 setup.py install --prefix=/app" ]
-        },
         {
             "name": "gexiv2",
             "modules": [