Add build verification using GitHub Actions

[samtstern]

Since this repository is used for snippets that are included in docs, the code here should have some automated verification that it compiles. Travis CI would be ideal as it's consistent with other Firebase Github projects.

Unit testing is not required but is a nice-to-have.

[crazyhappygame]

+1 please add Travis configuration for Android and iOS

[MdAbulHossain1]

import (
"fmt"
"context"

firebase "firebase.google.com/go"
"firebase.google.com/go/auth"

"google.golang.org/api/option"
)

opt := option.WithCredentialsFile("path/to/serviceAccountKey.json")
app, err := firebase.NewApp(context.Background(), nil, opt)
if err != nil {
return nil, fmt.Errorf("error initializing app: %v", err)
}

import firebase_admin
from firebase_admin import credentials

cred = credentials.Certificate("path/to/serviceAccountKey.json")
firebase_admin.initialize_app(cred)

FileInputStream serviceAccount =
new FileInputStream("path/to/serviceAccountKey.json");

FirebaseOptions options = new FirebaseOptions.Builder()
.setCredentials(GoogleCredentials.fromStream(serviceAccount))
.build();

FirebaseApp.initializeApp(options);

var admin = require("firebase-admin");

var serviceAccount = require("path/to/serviceAccountKey.json");

admin.initializeApp({
credential: admin.credential.cert(serviceAccount)
});

[DellaBitta]

Working on this, but using Github Actions instead of Travis CI.