Update dependency backbone to v1.4.1

This MR contains the following updates:

Package	Type	Update	Change	References
backbone	dependencies	minor	1.2.3 -> 1.4.1	source

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Release Notes

jashkenas/backbone

v1.4.1

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v1.4.0

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v1.3.3

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v1.3.2

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v1.3.1

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