chore: improve travis build for android

.travis.yml

@@ -9,7 +9,6 @@ matrix:
   include:
     - name: "iOS Build & Test"
       language: objective-c
-      sudo: false
       os: osx
       osx_image: xcode12.5
 
@@ -29,12 +28,20 @@ matrix:
 
     - name: "Android Build & Test"
       language: android
-      sudo: required
 
       android:
         components:
           - tools
 
+      before_cache:
+        -rm -f $HOME/.gradle/caches/modules-2/modules-2.lock
+        -rm -rf $HOME/.gradle/caches/*/plugin-resolution/
+
+      cache:
+        directories:
+        -$HOME/.gradle/caches/
+        -$HOME/.gradle/wrapper/
+
       before_install:
         - export LANG=en_US.UTF-8 &&
           curl -sL https://deb.nodesource.com/setup_14.x | sudo -E bash - &&