Update and rename firebase-cpp-sdk-issue.md to issue.md

Author: chkuang-g

.github/ISSUE_TEMPLATE/firebase-cpp-sdk-issue.md

@@ -0,0 +1,35 @@
+---
+name: Firebase C++ Sample issue
+about: Report issues with the Firebase C++ Sample.
+labels: new
+---
+<!-- DO NOT DELETE
+validate_template=true
+template_path=.github/ISSUE_TEMPLATE/issue.md
+-->
+
+### [READ] For Firebase C++ SDK issues, please report to [Firebase C++ open-source](https://github.com/firebase/firebase-cpp-sdk/issues)
+
+Once you've read this section and determined that your issue is appropriate for this repository, please delete this section.
+
+### [REQUIRED] Please fill in the following fields:
+
+  * Which Firebase Sample? (Auth, Database, etc.): _____
+  * Firebase C++ SDK version: _____
+  * Additional SDKs you are using (Facebook, AdMob, etc.): _____
+  * Platform you are using the SDK on (Mac, Windows, or Linux): _____
+  * Platform you are targeting (iOS, Android, and/or desktop): _____
+
+### [REQUIRED] Please describe the issue here:
+
+(Please list the full steps to reproduce the issue. Include device logs, and stack traces if available.)
+
+#### Steps to reproduce:
+
+What's the issue repro rate? (eg 100%, 1/5 etc)
+
+What happened? How can we make the problem occur?
+This could be a description, log/console output, etc.
+
+If you have a downloadable sample project that reproduces the bug you're reporting, you will
+likely receive a faster response on your issue.