Update the nodejs version to 14, for Firebase CLI

[a-maurice]

Description

Provide details of the change, and generalize the change in the PR title above.

Update the nodejs version to 14, since the Firebase CLI seems to require it now.

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Testing

Describe how you've tested these changes. Link any manually triggered Integration tests or CPP binary SDK Packaging Github Action workflows, if applicable.

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Type of Change

Place an x the applicable box:

• Bug fix. Add the issue # below if applicable.
• New feature. A non-breaking change which adds functionality.
• Other, such as a build process or documentation change.

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Notes

• Bug fixes and feature changes require an update to the Release Notes section of release_build_files/readme.md.
• Read the contribution guidelines CONTRIBUTING.md.
• Changes to the public API require an internal API review. If you'd like to help us make Firebase APIs better, please propose your change in a feature request so that we can discuss it together.

[github-actions]

❌  Integration test FAILED

Requested by @a-maurice on commit 091a0d7
Last updated: Thu May 19 20:10 PDT 2022
View integration test log & download artifacts

Failures	Configs
firestore	(5 items) [TEST] [ERROR] [Android] [All 2 os] [emulator_target] [TEST] [ERROR] [iOS] [macos] [1/2 ios_device: simulator_target] [TEST] [ERROR] [tvOS] [macos] [tvos_simulator] [TEST] [FLAKINESS] [Android] [1/2 os: ubuntu] [android_target] (1 failed tests)   CRASH/TIMEOUT [TEST] [FLAKINESS] [iOS] [macos] [1/2 ios_device: ios_target] (1 failed tests)   CRASH/TIMEOUT

Add flaky tests to go/fpl-cpp-flake-tracker

[sunmou99]

LGTM