Change iOS plugin so compiles for Xcode 11

[marchinram]

Also remove parse dependency not needed and set presenting view controller

[ragavendranbala]

Does it works on android also? Or need to use the official release only?

[marchinram]

Yeah I use it for both, Android wasn't causing me any issues, only the generated Xcode project had errors

[ragavendranbala]

Can you tell me how to download your pull request to fix the iOS issue on my project?

[marchinram]

You just run the build script sh build_all.sh I tried and saw a problem with the script will look into this

[marchinram]

Should work ok my only issue was I didn't set the UNITY_EXE env variable to the location of Unity executable, e.g: /Applications/Unity/Hub/Editor/2019.2.10f1/Unity.app/Contents/MacOS/Unity, after it's complete produces 2 .unitypackage files, google-signin-plugin-1.0.4.unitypackage and GoogleSignIn-sample.unitypackage, lemme know if you have issues with this @ragavendranbala

[marchinram]

handled here: #126