update version number to 9.1

6 jobs for master in 9 minutes and 45 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #14292
macos
build_macos

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ubuntu1604
build_ubuntu1604

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ubuntu1804
build_ubuntu1804

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passed #14295
ubuntu1804-gcc8
build_ubuntu1804-gcc8

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passed #14296
vc191x
build_vc191x

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passed #14297
vc192x
build_vc192x

00:08:32