chore(ci): update GitHub Actions (#1088)

* chore(ci): update GitHub Actions
* update gradle-wrapper and revert UPX
* exclude cargo from dependabot and remove empty .gitmodules

.github/dependabot.yaml

@@ -0,0 +1,34 @@
+# https://docs.github.com/en/code-security/dependabot/working-with-dependabot/dependabot-options-reference#package-ecosystem-
+
+version: 2
+updates:
+  # cargo updates are considered unstable without greater CI coverage
+  - package-ecosystem: gradle
+    directories:
+      - "easytier-gui/src-tauri/gen/android"
+      - "easytier-gui/src-tauri/gen/android/app"
+      - "easytier-gui/src-tauri/gen/android/buildSrc"
+      - "tauri-plugin-vpnservice/android"
+    schedule:
+      interval: weekly
+  - package-ecosystem: npm
+    directories:
+      - "/"
+      - "easytier-gui"
+      - "easytier-web/frontend"
+      - "easytier-web/frontend-lib"
+      - "tauri-plugin-vpnservice"
+    schedule:
+      interval: weekly
+  - package-ecosystem: docker
+    directory: ".github/workflows"
+    schedule:
+      interval: weekly
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly
+  - package-ecosystem: swift
+    directory: "tauri-plugin-vpnservice/ios"
+    schedule:
+      interval: weekly