Add opencv to flatpak

Dependency of KQuickImageEditor

.flatpak-manifest.json

@@ -44,6 +44,22 @@
                 }
             ]
         },
+        {
+            "name": "opencv",
+            "config-opts": [
+                "-DBUILD_TESTS=OFF",
+                "-DWITH_GTK=OFF",
+                "-DBUILD_LIST=core,imgproc"
+            ],
+            "buildsystem": "cmake-ninja",
+            "sources": [
+                {
+                    "type": "git",
+                    "url": "https://github.com/opencv/opencv"
+                }
+            ],
+            "builddir": true
+        },
         {
             "name": "kquickimageeditor",
             "config-opts": [