6.1.0 (polyfill.io vulnerability)

What's Changed

• Use the UMD build of intl-messageformat in the testsuite by @stof in #361
• remove polyfill.io becouse of security by @karion in #359
• fix broken link by @tacman in #353
• Prepare 6.1 version by @monteiro in #366

New Contributors

• @karion made their first contribution in #359
• @tacman made their first contribution in #353

Thanks @karion @tacman and @stof for helping this release.

Full Changelog: 6.0.0...6.1.0