DOC: Remove Travis and Coverity badges from README.md

9 jobs for !502 with readme-remove-badges in 10 seconds (queued for 1 second)
latest detached
Status Job ID Name Coverage
  Precheck
canceled #4475
fast-build

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  Prepare
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centos-superbuild-prepare
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macos
macos-superbuild-prepare
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ubuntu-superbuild-prepare
 
  Build
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centos-superbuild-build
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debian-build
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macos
macos-superbuild-build
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ubuntu-llvm
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ubuntu-superbuild-build