Bumps bootstrap-sass from 3.3.7 to 3.4.3.

Sourced from bootstrap-sass's releases.

v3.4.1

• Security: Fixed an XSS vulnerability (CVE-2019-8331) in our tooltip and popover plugins by implementing a new HTML sanitizer
• Handle bad selectors (#) in data-target for Dropdowns
• Clarified tooltip selector documentation
• Added support for NuGet contentFiles

v3.4.0

• New: Added a .row-no-gutters class.
• New: Added docs searching via Algolia.
• Fixed: Resolved an XSS issue in Alert, Carousel, Collapse, Dropdown, Modal, and Tab components. See https://snyk.io/vuln/npm:bootstrap:20160627 for details.
• Fixed: Added padding to .navbar-fixed-* on modal open
• Fixed: Removed the double border on elements.
• Removed Gist creation in web-based Customizer since anonymous gists were disabled long ago by GitHub.
• Removed drag and drop support from Customizer since it didn’t work anymore.

Framework version: Bootstrap v3.4.0 See the upstream blog post for a detailed overview.

Sourced from bootstrap-sass's changelog.

3.4.3 (non-ruby only)

• Fix malformed math.div expressions. #1225

3.4.2 (non-ruby only)

• Compatibility with Sass 1.33. #1221

3.4.0

• Bootstrap rubygem now depends on SassC instead of Sass.
• Compass no longer supported.

• 6b0ca50 Bump to 3.4.3 (npm only)
• 62dd931 rake convert[v3.4.1]
• 96917c6 replace_division: balance parens
• e2ecd03 Bump to 3.4.2 (npm only)
• 0512858 package.json: node-sass -> sass
• 3c6cbc0 rake convert[v3.4.1]
• 2f38fa5 handle math.div
• b34765d Rakefile: require 'bundler/gem_tasks'
• 143aa6a Bump bootstrap-sass to 3.4.1
• 69157ce rake convert[v3.4.1]
• Additional commits viewable in compare view

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