Add package.include to Cargo.toml

This reduces package size and notably prevents any bash files from landing on a users device.

android-activity/Cargo.toml

@@ -9,6 +9,13 @@ repository = "https://github.com/rust-mobile/android-activity"
 documentation = "https://docs.rs/android-activity"
 description = "Glue for building Rust applications on Android with NativeActivity or GameActivity"
 license = "MIT OR Apache-2.0"
+include = [
+    "/build.rs",
+    "/docs",
+    "/game-activity-csrc",
+    "/LICENSE",
+    "/src/**/*.rs",
+]
 
 # 1.69 was when Rust last updated the Android NDK version used to build the
 # standard library which avoids needing the -lunwind workaround in build tools.