[4.5.1] - 2019-08-01

Fixed

• Fix #2187. Bump core-js and update core-js modules on index-es5.js, by @corinagum in PR #2195
• Fix #2193. Fix Adaptive Card/attachments do not get read by Narrator, by @corinagum in PR #2226
• Fix #2150. Fix timestamps read by Narrator, by @corinagum in PR #2226
• Fix #2250. Fix React warnings related prop types, by @compulim in PR #2253

Subresource Integrity

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