Release Artifacts for v2.3.7

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Make the attrs of non-element vnodes always non-null.

In #3041, it seemed that the case of non-element vnodes was not fully considered in terms of not breaking existing behavior.

Release Artifacts for v2.3.5

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Release Artifacts for v2.3.4

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Release Artifacts for v2.3.3

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Release Artifacts for v2.3.2

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Release Artifacts for v2.3.1

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Release Artifacts for v2.3.0

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Release Artifacts for v2.2.15

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Release Artifacts for v2.2.14

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