CI: Add local exceptions to flatpak-builder-lint

For some reason the action can no longer check if the URL generated in
the metainfo is reachable.
So to avoid keeping CI failing, local exceptions rule are
added.

Unfortunately it requires to keep a copy of exceptions already submitted
to Flathub.

.github/actions/flatpak-builder-lint/action.yaml

@@ -32,7 +32,7 @@ runs:
         : Run flatpak-builder-lint
 
         return=0
-        result="$(flatpak-builder-lint --exceptions ${{ inputs.artifact }} ${{ inputs.path }})" || return=$?
+        result="$(flatpak-builder-lint --exceptions --user-exceptions ${GITHUB_ACTION_PATH}/exceptions.json ${{ inputs.artifact }} ${{ inputs.path }})" || return=$?
 
         if [[ ${return} != 0 && -z "${result}" ]]; then
           echo "::error::Error while running flatpak-builder-lint"

.github/actions/flatpak-builder-lint/exceptions.json

@@ -0,0 +1,8 @@
+{
+  "com.obsproject.Studio": [
+    "finish-args-flatpak-spawn-access",
+    "external-gitmodule-url-found",
+    "finish-args-host-filesystem-access",
+    "appstream-flathub-manifest-url-not-reachable"
+  ]
+}