Maven Compile Warning for SuppressFBWarnings

### Problem:

Introducing the dependency on `aws-encryption-sdk-java` introduces compile warnings about `edu.umd.cs.findbugs.annotations.SuppressFBWarnings`

For example:
```
Cannot find annotation method 'value()' in type 'edu.umd.cs.findbugs.annotations.SuppressFBWarnings': class file for edu.umd.cs.findbugs.annotations.SuppressFBWarnings not found
```

### Solution:

Options:
* Change the scope of the `com.google.code.findbugs` to compile.
* Document the potential warnings and suggest fixes like declaring dependencies in your own project

### Out of scope:

I'm sure there are different options for handling this and they may vary depending on the build tool being used.

首先在引入 aws-encryption-sdk-java 后复现 Maven 编译警告，然后检查 com.google.code.findbugs 依赖的 scope 是如何设置的。比较将其改为 compile scope 与记录该警告并采用项目级依赖 workaround 两种方式；完成的标准是选定的处理方式已实现，并且已验证警告行为。

由索引模型根据 Issue 内容生成。