flatpak: Add Jansson to modules

CI/flatpak/com.obsproject.Studio.json

@@ -386,6 +386,29 @@
         }
       ]
     },
+    {
+      "name": "jansson",
+      "buildsystem": "cmake-ninja",
+      "builddir": true,
+      "config-opts": [
+        "-DJANSSON_EXAMPLES=OFF",
+        "-DJANSSON_BUILD_DOCS=OFF",
+        "-DJANSSON_BUILD_SHARED_LIBS=ON",
+        "-DJANSSON_WITHOUT_TESTS=ON"
+      ],
+      "cleanup": [
+        "/include",
+        "/lib/pkgconfig"
+      ],
+      "sources": [
+        {
+          "type": "git",
+          "url": "https://github.com/akheron/jansson.git",
+          "tag": "v2.14",
+          "commit": "684e18c927e89615c2d501737e90018f4930d6c5"
+        }
+      ]
+    },
     {
       "name": "cef",
       "buildsystem": "cmake-ninja",