build: add issue template

The Dapr CPP SDK repo should have an issues template for when end users create issues when working with the project.

Describe the solution you'd like
We should abide by a standardized issue template across all SDK repositories.

To implement, we should add a `ISSUE_TEMPLATE` directory similar to that of:
https://github.com/dapr/java-sdk/tree/master/.github/ISSUE_TEMPLATE
https://github.com/dapr/python-sdk/tree/master/.github/ISSUE_TEMPLATE

Additional context
This will help to improve contributors to easily communicate their issues, as well as maintainers to easily understand what the issue at hand is.

查看 Dapr Java 和 Python SDK 仓库中链接的 .github/ISSUE_TEMPLATE 目录，以了解标准化的 issue 表单。将对应的模板目录添加到此仓库，并在最终用户拥有用于报告问题的一致 issue 模板后，视为工作完成。

由索引模型根据 Issue 内容生成。