Update pub.dev workflow for platform_interface (#354)

The first attempt failed because of
dart-lang/setup-dart#68. This uses the
--skip-validation option recommended in that issue.

Apparently the workflow recommended by pub.dev actually doesn't work
with Flutter plugins because it tries to do some client side validations
that fail because the workflow does not setup Flutter...

.github/workflows/pub-platform-interface-publish.yml

@@ -4,11 +4,20 @@ on:
   push:
     tags:
       - 'pub-maplibre_gl_platform_interface-[0-9]+.[0-9]+.[0-9]+*'
+  workflow_dispatch:
 
 jobs:
   publish:
     permissions:
       id-token: write # Required for authentication using OIDC
-    uses: dart-lang/setup-dart/.github/workflows/publish.yml@v1
-    with:
-      working-directory: maplibre_gl_platform_interface
+    runs-on: ubuntu-latest
+    steps:
+      # Checkout repository
+      - uses: actions/checkout@v4
+      # Setup Dart SDK with JWT token
+      - uses: dart-lang/setup-dart@b64355ae6ca0b5d484f0106a033dd1388965d06d
+      # Publishing...
+      # skip validation due to https://github.com/dart-lang/setup-dart/issues/68
+      - name: Publish to pub.dev
+        run: dart pub publish -f --skip-validation
+        working-directory: maplibre_gl_platform_interface