replace warning emoji with warning unicode

[niccokunzmann]

Due to the use of the emoji, the documentation page shows
⚠️ instead of ⚠.
https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-camera/index.html

I would like to create an issue but I am not able to find the project here: https://issues.apache.org/jira/secure/CreateIssue.jspa

Platforms affected

What does this PR do?

What testing has been done on this change?

Checklist

• Reported an issue in the JIRA database
• Commit message follows the format: "CB-3232: (android) Fix bug with resolving file paths", where CB-xxxx is the JIRA ID & "android" is the platform affected.
• Added automated test coverage as appropriate for this change.

[jcesarmobile]

Hi,

Thanks for the contribution.
The project to choose on jira is "Apache Cordova", then you can add cordova-plugin-camera as component.

As it's an small change I'll merge anyway, but next time you know how to do it ;)

Thanks!