Bump firebase from 7.6.1 to 7.6.2

Bumps [firebase](https://github.com/firebase/firebase-js-sdk) from 7.6.1 to 7.6.2.
- [Release notes](https://github.com/firebase/firebase-js-sdk/releases)
- [Commits](https://github.com/firebase/firebase-js-sdk/compare/firebase@7.6.1...firebase@7.6.2)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -12,7 +12,7 @@
     "codemirror": "^5.50.2",
     "cross-env": "^6.0.3",
     "crypto-js": "^3.1.9-1",
-    "firebase": "^7.6.1",
+    "firebase": "^7.6.2",
     "immutable": "^3.8.2",
     "node-sass": "^4.13.0",
     "react": "^16.12.0",