feat: Update to NodeJS 14.x

[gliptak]

Signed-off-by: Gábor Lipták [email protected]

Fixes #
#439

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[gliptak]

25h/home/runner/work/aws-cdk-examples/aws-cdk-examples/typescript/ecs/fargate-service-with-efs/node_modules/@aws-cdk/aws-lambda/lib/function.js:650
        throw new Error(`Inline source not allowed for ${props.runtime.name}`);
        ^

maybe we are to fall back to 12.x?

PS is above restriction still valid?

aws/aws-cdk#13226